diff --git a/app/controllers/dmsf_controller.rb b/app/controllers/dmsf_controller.rb
index 7e6be110..9d50c59d 100644
--- a/app/controllers/dmsf_controller.rb
+++ b/app/controllers/dmsf_controller.rb
@@ -38,7 +38,7 @@ class DmsfController < ApplicationController
   helper :dmsf_folder_permissions
 
   def permissions
-    render_403 unless DmsfFolder.permissions(@folder)
+    render_403 unless DmsfFolder.permissions?(@folder)
     true
   end
 
@@ -80,7 +80,7 @@ class DmsfController < ApplicationController
     @file_manipulation_allowed = User.current.allowed_to? :file_manipulation, @project
     @file_delete_allowed = User.current.allowed_to? :file_delete, @project
     @subfolders = DmsfFolder.deleted.where(:project_id => @project.id)
-    @files = DmsfFile.deleted.where(:container_id => @project.id, :container_type => 'Project')
+    @files = DmsfFile.deleted.where(:project_id => @project.id)
     @dir_links = DmsfLink.deleted.where(:project_id => @project.id, :target_type => DmsfFolder.model_name.to_s)
     @file_links = DmsfLink.deleted.where(:project_id => @project.id, :target_type => DmsfFile.model_name.to_s)
     @url_links = DmsfLink.deleted.where(:project_id => @project.id, :target_type => 'DmsfUrl')
@@ -643,6 +643,7 @@ class DmsfController < ApplicationController
   private
 
   def get_display_params
+    @system_folder = @folder && @folder.system
     @folder_manipulation_allowed = User.current.allowed_to?(:folder_manipulation, @project)
     @file_manipulation_allowed = User.current.allowed_to?(:file_manipulation, @project)
     @file_delete_allowed = User.current.allowed_to?(:file_delete, @project)
@@ -658,7 +659,7 @@ class DmsfController < ApplicationController
       if tag
         @subfolders = []
         folder_id = @folder.id if @folder
-        DmsfFolder.where(:project_id => @project.id, :dmsf_folder_id => folder_id).visible.each do |f|
+        DmsfFolder.where(:project_id => @project.id, :dmsf_folder_id => folder_id, :system => false).visible.each do |f|
           f.custom_field_values.each do |v|
             if v.custom_field_id == params[:custom_field_id].to_i
               if v.custom_field.compare_values?(v.value, params[:custom_value])
@@ -669,7 +670,7 @@ class DmsfController < ApplicationController
           end
         end
         @files = []
-        DmsfFile.where(:container_id => @project.id, :container_type => 'Project', :dmsf_folder_id => folder_id).visible.each do |f|
+        DmsfFile.where(:project_id => @project.id, :dmsf_folder_id => folder_id).visible.each do |f|
           r = f.last_revision
           if r
             r.custom_field_values.each do |v|
@@ -733,7 +734,7 @@ class DmsfController < ApplicationController
     @trash_visible = @folder_manipulation_allowed && @file_manipulation_allowed &&
       @file_delete_allowed && !@locked_for_user && !@folder
     @trash_enabled = DmsfFolder.deleted.where(:project_id => @project.id).any? ||
-      DmsfFile.deleted.where(:container_id => @project.id, :container_type => 'Project').any? ||
+      DmsfFile.deleted.where(:project_id => @project.id).any? ||
       DmsfLink.deleted.where(:project_id => @project.id).any?
   end
 
diff --git a/app/controllers/dmsf_files_controller.rb b/app/controllers/dmsf_files_controller.rb
index 87277503..9aaf4831 100644
--- a/app/controllers/dmsf_files_controller.rb
+++ b/app/controllers/dmsf_files_controller.rb
@@ -38,7 +38,7 @@ class DmsfFilesController < ApplicationController
 
   def permissions
     if @file
-      render_403 unless DmsfFolder.permissions(@file.dmsf_folder)
+      render_403 unless DmsfFolder.permissions?(@file.dmsf_folder)
     end
     true
   end
@@ -192,7 +192,7 @@ class DmsfFilesController < ApplicationController
       commit = params[:commit] == 'yes'
       if @file.delete(commit)
         flash[:notice] = l(:notice_file_deleted)
-        if commit && (@file.container_type == 'Project')
+        if commit
           log_activity('deleted')
           begin
             recipients = DmsfMailer.get_notify_users(@project, [@file])
diff --git a/app/controllers/dmsf_folder_permissions_controller.rb b/app/controllers/dmsf_folder_permissions_controller.rb
index 062663e1..f2410fb8 100644
--- a/app/controllers/dmsf_folder_permissions_controller.rb
+++ b/app/controllers/dmsf_folder_permissions_controller.rb
@@ -27,7 +27,7 @@ class DmsfFolderPermissionsController < ApplicationController
   before_filter :permissions
 
   def permissions
-    render_403 unless DmsfFolder.permissions(@dmsf_folder)
+    render_403 unless DmsfFolder.permissions?(@dmsf_folder)
     true
   end
 
diff --git a/app/controllers/dmsf_folders_copy_controller.rb b/app/controllers/dmsf_folders_copy_controller.rb
index a2720eb3..27f022c9 100644
--- a/app/controllers/dmsf_folders_copy_controller.rb
+++ b/app/controllers/dmsf_folders_copy_controller.rb
@@ -26,7 +26,7 @@ class DmsfFoldersCopyController < ApplicationController
   before_filter :permissions
 
   def permissions
-    render_403 unless DmsfFolder.permissions(@folder)
+    render_403 unless DmsfFolder.permissions?(@folder)
     true
   end
 
diff --git a/app/controllers/dmsf_links_controller.rb b/app/controllers/dmsf_links_controller.rb
index eb4a0921..08b0fce3 100644
--- a/app/controllers/dmsf_links_controller.rb
+++ b/app/controllers/dmsf_links_controller.rb
@@ -29,7 +29,7 @@ class DmsfLinksController < ApplicationController
 
   def permissions
     if @dmsf_link
-      render_403 unless DmsfFolder.permissions(@dmsf_link.dmsf_folder)
+      render_403 unless DmsfFolder.permissions?(@dmsf_link.dmsf_folder)
     end
     true
   end
diff --git a/app/controllers/dmsf_upload_controller.rb b/app/controllers/dmsf_upload_controller.rb
index 818b58da..d122e115 100644
--- a/app/controllers/dmsf_upload_controller.rb
+++ b/app/controllers/dmsf_upload_controller.rb
@@ -36,7 +36,7 @@ class DmsfUploadController < ApplicationController
   accept_api_auth :upload, :commit
 
   def permissions
-    render_403 unless DmsfFolder.permissions(@folder)
+    render_403 unless DmsfFolder.permissions?(@folder)
     true
   end
 
diff --git a/app/controllers/dmsf_workflows_controller.rb b/app/controllers/dmsf_workflows_controller.rb
index e87381d2..45536c74 100644
--- a/app/controllers/dmsf_workflows_controller.rb
+++ b/app/controllers/dmsf_workflows_controller.rb
@@ -32,7 +32,7 @@ class DmsfWorkflowsController < ApplicationController
   def permissions
     revision = DmsfFileRevision.find_by_id params[:dmsf_file_revision_id] if params[:dmsf_file_revision_id].present?
     if revision
-      render_403 unless revision.dmsf_file || DmsfFolder.permissions(revision.dmsf_file.dmsf_folder)
+      render_403 unless revision.dmsf_file || DmsfFolder.permissions?(revision.dmsf_file.dmsf_folder)
     end
     true
   end
diff --git a/app/helpers/dmsf_upload_helper.rb b/app/helpers/dmsf_upload_helper.rb
index 78d292ac..ef08fd7d 100644
--- a/app/helpers/dmsf_upload_helper.rb
+++ b/app/helpers/dmsf_upload_helper.rb
@@ -21,20 +21,15 @@
 module DmsfUploadHelper
   include Redmine::I18n
 
-  def self.commit_files_internal(commited_files, container, folder, controller)
+  def self.commit_files_internal(commited_files, project, folder, controller)
     failed_uploads = []
     files = []
-    if container.is_a?(Project)
-      project = container
-    else
-      project = container.project
-    end
     if commited_files && commited_files.is_a?(Hash)
       failed_uploads = []
       commited_files.each_value do |commited_file|
         name = commited_file[:name]
         new_revision = DmsfFileRevision.new
-        file = DmsfFile.visible.find_file_by_name(container, folder, name)
+        file = DmsfFile.visible.find_file_by_name(project, folder, name)
         unless file
           link = DmsfLink.find_link_by_file_name(project, folder, name)
           file = link.target_file if link
@@ -42,8 +37,7 @@ module DmsfUploadHelper
 
         unless file
           file = DmsfFile.new
-          file.container_type = container.class.name.demodulize
-          file.container_id = container.id
+          file.project_id = project.id
           file.name = name
           file.dmsf_folder = folder
           file.notification = Setting.plugin_redmine_dmsf[:dmsf_default_notifications].present?
@@ -119,7 +113,7 @@ module DmsfUploadHelper
           failed_uploads.push(commited_file)
         end
       end
-      if container.is_a?(Project) && ((folder && folder.notification?) || (!folder && project.dmsf_notification?))
+      if ((folder && folder.notification?) || (!folder && project.dmsf_notification?))
         begin
           recipients = DmsfMailer.get_notify_users(project, files)
           recipients.each do |u|
diff --git a/app/models/dmsf_file.rb b/app/models/dmsf_file.rb
index 4788c9bb..870b22a7 100644
--- a/app/models/dmsf_file.rb
+++ b/app/models/dmsf_file.rb
@@ -32,6 +32,7 @@ class DmsfFile < ActiveRecord::Base
 
   include RedmineDmsf::Lockable
 
+  belongs_to :project
   belongs_to :dmsf_folder
   belongs_to :deleted_by_user, :class_name => 'User', :foreign_key => 'deleted_by_user_id'
 
@@ -58,7 +59,7 @@ class DmsfFile < ActiveRecord::Base
   attr_accessible :project, :project_id
 
   def validates_name_uniqueness
-    existing_file = DmsfFile.visible.findn_file_by_name(self.container_id, self.container_type, self.dmsf_folder, self.name)
+    existing_file = DmsfFile.visible.findn_file_by_name(self.project_id, self.dmsf_folder, self.name)
     errors.add(:name, l('activerecord.errors.messages.taken')) unless (existing_file.nil? || existing_file.id == self.id)
   end
 
@@ -120,14 +121,13 @@ class DmsfFile < ActiveRecord::Base
     @@storage_path = path
   end
 
-  def self.find_file_by_name(container, folder, name)
-    self.findn_file_by_name(container.id, container.class.name.demodulize, folder, name)
+  def self.find_file_by_name(project, folder, name)
+    self.findn_file_by_name(project.id, folder, name)
   end
 
-  def self.findn_file_by_name(container_id, container_type, folder, name)
+  def self.findn_file_by_name(project_id, folder, name)
     where(
-      :container_id => container_id,
-      :container_type => container_type,
+      :project_id => project_id,
       :dmsf_folder_id => folder ? folder.id : nil,
       :name => name).visible.first
   end
@@ -249,19 +249,17 @@ class DmsfFile < ActiveRecord::Base
     projects
   end
 
-  def move_to(container, folder)
+  def move_to(project, folder)
     if self.locked_for_user?
       errors[:base] << l(:error_file_is_locked)
       return false
     end
     # Must invalidate source parent folder cache before moving
     RedmineDmsf::Webdav::Cache.invalidate_item(propfind_cache_key)
-    self.container_type = self.container_type
-    self.container_id = container.id
+    self.project_id = project.id
     self.dmsf_folder = folder
     new_revision = self.last_revision.clone
     new_revision.dmsf_file = self
-    project = container.is_a?(Project) ? container : container.project
     new_revision.comment = l(:comment_moved_from, :source => "#{self.project.identifier}:#{self.dmsf_path_str}")
     new_revision.custom_values = []
     self.last_revision.custom_values.each do |cv|
@@ -271,15 +269,14 @@ class DmsfFile < ActiveRecord::Base
     self.save && new_revision.save
   end
 
-  def copy_to(container, folder = nil)
-    copy_to_filename(container, folder, self.name)
+  def copy_to(project, folder = nil)
+    copy_to_filename(project, folder, self.name)
   end
   
-  def copy_to_filename(container, folder=nil, filename)
+  def copy_to_filename(project, folder, filename)
     file = DmsfFile.new
     file.dmsf_folder = folder
-    file.container_type = self.container_type
-    file.container_id = container.id
+    file.project_id = project.id
     file.name = filename
     file.notification = Setting.plugin_redmine_dmsf['dmsf_default_notifications'].present?
     if file.save && self.last_revision
@@ -289,7 +286,6 @@ class DmsfFile < ActiveRecord::Base
       if File.exist? self.last_revision.disk_file
         FileUtils.cp self.last_revision.disk_file, new_revision.disk_file
       end
-      project = container.is_a?(Project) ? container : container.project
       new_revision.comment = l(:comment_copied_from, :source => "#{project.identifier}: #{self.dmsf_path_str}")
       new_revision.custom_values = []
       self.last_revision.custom_values.each do |cv|
@@ -325,8 +321,7 @@ class DmsfFile < ActiveRecord::Base
     project_conditions << Project.allowed_to_condition(user, :view_dmsf_files)
     project_conditions << "#{Project.table_name}.id IN (#{project_ids.join(',')})" if project_ids.present?
 
-    scope = self.visible.joins(:dmsf_file_revisions).joins(
-      "JOIN  #{Project.table_name} ON #{DmsfFile.table_name}.container_id = #{Project.table_name}.id AND #{DmsfFile.table_name}.container_type = 'Project'")
+    scope = self.visible.joins(:dmsf_file_revision).joins(:project)
     scope = scope.limit(options[:limit]) unless options[:limit].blank?
     scope = scope.where(limit_options) unless limit_options.blank?
     scope = scope.where(project_conditions.join(' AND '))
@@ -516,13 +511,11 @@ class DmsfFile < ActiveRecord::Base
   end
   
   def propfind_cache_key
-    if self.container_type == 'Project'
-      if dmsf_folder_id.nil?
-        # File is in project root
-        return "PROPFIND/#{self.container_id}"
-      else
-        return "PROPFIND/#{self.container_id}/#{self.dmsf_folder_id}"
-      end
+    unless dmsf_folder_id
+      # File is in project root
+      return "PROPFIND/#{self.project_id}"
+    else
+      return "PROPFIND/#{self.project_id}/#{self.dmsf_folder_id}"
     end
   end
 
@@ -606,31 +599,6 @@ class DmsfFile < ActiveRecord::Base
     csv
   end
 
-  def project
-    unless @project
-      case self.container_type
-        when 'Project'
-          @project = Project.find_by_id(self.container_id)
-        when 'Issue'
-          issue = Issue.find_by_id(self.container_id)
-          @project = issue.project if issue
-      end
-    end
-    @project
-  end
-
-  def container
-    unless @container
-      case self.container_type
-        when 'Project'
-          @container = Project.find_by_id(self.container_id)
-        when 'Issue'
-          @container = Issue.find_by_id(self.container_id)
-      end
-    end
-    @container
-  end
-
   def thumbnail(options={})
     if image?
       size = options[:size].to_i
@@ -665,4 +633,10 @@ class DmsfFile < ActiveRecord::Base
     l(:title_unlock_file)
   end
 
+  def container
+    if self.dmsf_folder && self.dmsf_folder.system
+      Issue.where(:id => self.dmsf_folder.title.to_i).first
+    end
+  end
+
 end
diff --git a/app/models/dmsf_file_revision.rb b/app/models/dmsf_file_revision.rb
index 87378718..26e5a46f 100644
--- a/app/models/dmsf_file_revision.rb
+++ b/app/models/dmsf_file_revision.rb
@@ -49,10 +49,8 @@ class DmsfFileRevision < ActiveRecord::Base
     :timestamp => "#{DmsfFileRevision.table_name}.updated_at",
     :author_key => "#{DmsfFileRevision.table_name}.user_id",
     :permission => :view_dmsf_file_revisions,
-    :scope => select("#{DmsfFileRevision.table_name}.*").
-      joins(:dmsf_file).joins(
-        "LEFT JOIN #{Project.table_name} ON #{DmsfFile.table_name}.container_id = #{Project.table_name}.id").
-      where("#{DmsfFile.table_name}.container_type = ?", 'Project').visible
+    :scope => select("#{DmsfFileRevision.table_name}.*").joins(:dmsf_file).
+      joins("JOIN #{Project.table_name} ON #{Project.table_name}.id = #{DmsfFile.table_name}.project_id").visible
 
   validates :title, :presence => true
   validates_format_of :name, :with => DmsfFolder::INVALID_CHARACTERS,
diff --git a/app/models/dmsf_file_revision_access.rb b/app/models/dmsf_file_revision_access.rb
index f83223af..15fcb5b0 100644
--- a/app/models/dmsf_file_revision_access.rb
+++ b/app/models/dmsf_file_revision_access.rb
@@ -41,8 +41,6 @@ class DmsfFileRevisionAccess < ActiveRecord::Base
     :author_key => "#{DmsfFileRevisionAccess.table_name}.user_id",
     :permission => :view_dmsf_file_revision_accesses,
     :scope => select("#{DmsfFileRevisionAccess.table_name}.*").
-      joins(:dmsf_file_revision).joins(
-        "LEFT JOIN #{DmsfFile.table_name} ON #{DmsfFileRevision.table_name}.dmsf_file_id = #{DmsfFile.table_name}.id " +
-        "LEFT JOIN #{Project.table_name} ON #{DmsfFile.table_name}.container_id = #{Project.table_name}.id").
-      where("#{DmsfFile.table_name}.deleted = ? AND #{DmsfFile.table_name}.container_type = ?", DmsfFile::STATUS_ACTIVE, 'Project')
+      joins(:dmsf_file_revision).joins(:dmsf_file).
+      where(["#{DmsfFile.table_name}.deleted = ?", DmsfFile::STATUS_ACTIVE])
 end
diff --git a/app/models/dmsf_folder.rb b/app/models/dmsf_folder.rb
index cb3c9b8d..a1324ba8 100644
--- a/app/models/dmsf_folder.rb
+++ b/app/models/dmsf_folder.rb
@@ -50,14 +50,15 @@ class DmsfFolder < ActiveRecord::Base
   AVAILABLE_COLUMNS = %w(id title extension size modified version workflow author).freeze
   DEFAULT_COLUMNS = %w(title size modified version workflow author).freeze
 
-  scope :visible, -> { joins(:project).joins(
+  scope :visible, -> (system=true) { joins(:project).joins(
     "LEFT JOIN #{DmsfFolderPermission.table_name} ON #{DmsfFolder.table_name}.id = #{DmsfFolderPermission.table_name}.dmsf_folder_id").where(
-    :deleted => STATUS_ACTIVE).where(DmsfFolder.visible_condition).distinct
+    :deleted => STATUS_ACTIVE).where(DmsfFolder.visible_condition(system)).distinct
   }
   scope :deleted, -> { joins(:project).joins(
     "LEFT JOIN #{DmsfFolderPermission.table_name} ON #{DmsfFolder.table_name}.id = #{DmsfFolderPermission.table_name}.dmsf_folder_id").where(
     :deleted => STATUS_DELETED).where(DmsfFolder.visible_condition).distinct
   }
+  scope :system, -> { where(:system => true) }
 
   acts_as_customizable
 
@@ -83,8 +84,8 @@ class DmsfFolder < ActiveRecord::Base
 
   before_create :default_values
 
-  def self.visible_condition
-    Project.allowed_to_condition(User.current, :view_dmsf_folders) do |role, user|
+  def self.visible_condition(system=true)
+    sql = Project.allowed_to_condition(User.current, :view_dmsf_folders) do |role, user|
       if user.id && user.logged?
         %{
           (#{DmsfFolderPermission.table_name}.object_id IS NULL) OR
@@ -92,14 +93,16 @@ class DmsfFolder < ActiveRecord::Base
           (#{DmsfFolderPermission.table_name}.object_id = #{user.id} AND #{DmsfFolderPermission.table_name}.object_type = 'User')
         }
       else
-        '0=1'
+        '0 = 1'
       end
     end
+    "#{sql} AND (#{DmsfFolder.table_name}.system = 0 OR 1 = #{(system && Setting.plugin_redmine_dmsf['dmsf_show_system_folders']) ? 1 : 0})"
   end
 
-  def self.permissions(folder)
+  def self.permissions?(folder, allow_system = true)
+    return false if folder && folder.system && (!allow_system || !Setting.plugin_redmine_dmsf['dmsf_show_system_folders'])
     return true if (User.current.admin? || folder.nil?)
-    if !folder.dmsf_folder || permissions(folder.dmsf_folder)
+    if !folder.dmsf_folder || permissions?(folder.dmsf_folder, allow_system)
       if folder.dmsf_folder_permissions.any?
         role_ids = User.current.roles_for_project(folder.project).map{ |r| r.id }
         role_permission_ids = folder.dmsf_folder_permissions.roles.map{ |p| p.object_id }
@@ -205,7 +208,7 @@ class DmsfFolder < ActiveRecord::Base
 
   def self.directory_tree(project, current_folder = nil)
     tree = [[l(:link_documents), nil]]
-    project.dmsf_folders.visible.each do |folder|
+    project.dmsf_folders.visible(false).each do |folder|
       unless folder == current_folder
         tree.push(["...#{folder.title}", folder.id])
         directory_subtree(tree, folder, 2, current_folder)
@@ -316,8 +319,8 @@ class DmsfFolder < ActiveRecord::Base
        self.project_id, self.id, last_update]).maximum(:updated_at)
     last_update = time if time
     time = DmsfFile.where(
-      ['container_id = ? AND container_type = ? AND dmsf_folder_id = ? AND updated_at > ?',
-       self.project_id, 'Project', self.id, last_update]).maximum(:updated_at)
+      ['project_id = ? AND dmsf_folder_id = ? AND updated_at > ?',
+       self.project_id, self.id, last_update]).maximum(:updated_at)
     last_update = time if time
     time = DmsfLink.where(
       ['project_id = ? AND dmsf_folder_id = ? AND updated_at > ?',
@@ -329,7 +332,7 @@ class DmsfFolder < ActiveRecord::Base
   # Number of items in the folder
   def items
     dmsf_folders.visible.where(:project_id => self.project_id).count +
-    dmsf_files.visible.where(:container_id => self.project_id).count +
+    dmsf_files.visible.where(:project_id => self.project_id).count +
     dmsf_links.visible.where(:project_id => self.project_id).count
   end
 
@@ -351,6 +354,10 @@ class DmsfFolder < ActiveRecord::Base
   end
 
   def self.get_column_position(column)
+    unless @@dmsf_columns
+      @@dmsf_columns = Setting.plugin_redmine_dmsf['dmsf_columns']
+      @@dmsf_columns = DmsfFolder::DEFAULT_COLUMNS unless columns
+    end
     pos = 0
     # 0 - checkbox
     # 1 - id
@@ -517,7 +524,7 @@ class DmsfFolder < ActiveRecord::Base
   private
 
   def self.directory_subtree(tree, folder, level, current_folder)
-    folder.dmsf_folders.visible.each do |subfolder|
+    folder.dmsf_folders.visible(false).each do |subfolder|
       unless subfolder == current_folder
         tree.push(["#{'...' * level}#{subfolder.title}", subfolder.id])
         directory_subtree(tree, subfolder, level + 1, current_folder)
diff --git a/app/models/dmsf_upload.rb b/app/models/dmsf_upload.rb
index c56408a8..b9c25336 100644
--- a/app/models/dmsf_upload.rb
+++ b/app/models/dmsf_upload.rb
@@ -76,8 +76,7 @@ class DmsfUpload
       @minor_version = 0
       @workflow = nil
       file = DmsfFile.new
-      file.container_type = 'Project'
-      file.container_id = project.id
+      file.project_id = project.id
       revision = DmsfFileRevision.new
       revision.dmsf_file = file
       @custom_values = revision.custom_field_values
diff --git a/app/models/dmsf_workflow.rb b/app/models/dmsf_workflow.rb
index c7a6c87f..580e0de0 100644
--- a/app/models/dmsf_workflow.rb
+++ b/app/models/dmsf_workflow.rb
@@ -106,8 +106,8 @@ class DmsfWorkflow < ActiveRecord::Base
   def delegates(q, dmsf_workflow_step_assignment_id, dmsf_file_revision_id)
     if dmsf_workflow_step_assignment_id && dmsf_file_revision_id
       sql = [
-        'id NOT IN (SELECT a.user_id FROM dmsf_workflow_step_assignments a WHERE id = ?) AND id IN (SELECT m.user_id FROM members m JOIN dmsf_files f ON f.container_id = m.project_id JOIN dmsf_file_revisions r ON r.dmsf_file_id = f.id WHERE r.id = ? AND container_type = ?)',
-        dmsf_workflow_step_assignment_id, dmsf_file_revision_id, 'Project']
+        'id NOT IN (SELECT a.user_id FROM dmsf_workflow_step_assignments a WHERE id = ?) AND id IN (SELECT m.user_id FROM members m JOIN dmsf_files f ON f.project_id = m.project_id JOIN dmsf_file_revisions r ON r.dmsf_file_id = f.id WHERE r.id = ?)',
+        dmsf_workflow_step_assignment_id, dmsf_file_revision_id]
     elsif project
       sql = ['id IN (SELECT user_id FROM members WHERE project_id = ?)', project.id]
     else
diff --git a/app/views/dmsf/_dir.html.erb b/app/views/dmsf/_dir.html.erb
index 87b02ac5..7c4645a5 100644
--- a/app/views/dmsf/_dir.html.erb
+++ b/app/views/dmsf/_dir.html.erb
@@ -20,8 +20,11 @@
 # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 %>
 
-<td class="dmsf_checkbox"><%= check_box_tag(name, id, false,
-  :title => l(:title_check_for_zip_download_or_email), :id => "subfolder_#{id}") %></td>
+<td class="dmsf_checkbox">
+  <% unless (subfolder && subfolder.system) %>
+    <%= check_box_tag(name, id, false, :title => l(:title_check_for_zip_download_or_email), :id => "subfolder_#{id}") %>
+  <% end %>
+</td>
 <% if DmsfFolder.is_column_on?('id') %>
     <td class="id"><%= link_to(subfolder.id, edit_dmsf_path(:id => project, :folder_id => subfolder)) %></td>
 <% end %>
@@ -68,7 +71,7 @@
     <% end %>
 <% end %>
 <td class="dmsf_buttons">
-  <% if @folder_manipulation_allowed %>
+  <% if @folder_manipulation_allowed && !(subfolder && subfolder.system) %>
     <% if subfolder && subfolder.locked? %>
       <span class="icon"></span>
       <% if subfolder.unlockable? && (!subfolder.locked_for_user? || @force_file_unlock_allowed) %>
diff --git a/app/views/dmsf/_dmsf_rows.erb b/app/views/dmsf/_dmsf_rows.erb
index bd8f58cf..82c9d88a 100644
--- a/app/views/dmsf/_dmsf_rows.erb
+++ b/app/views/dmsf/_dmsf_rows.erb
@@ -19,6 +19,7 @@
     <% end %>
 
     <% if obj.is_a? DmsfFolder %>
+        <% classes << ' dmsf_system' if obj.system %>
         <tr <%= id %> class="dir <%= classes %>">
           <%= render(:partial => 'dir',
                      :locals => {
diff --git a/app/views/dmsf/_file.html.erb b/app/views/dmsf/_file.html.erb
index f9601572..059d666b 100644
--- a/app/views/dmsf/_file.html.erb
+++ b/app/views/dmsf/_file.html.erb
@@ -133,46 +133,9 @@
       <span class="icon"></span>
     <% end %>
   <% end %>
-  <% if @file_approval_allowed %>
-    <% case file.last_revision.workflow %>
-      <%  when DmsfWorkflow::STATE_WAITING_FOR_APPROVAL %>
-        <% if wf %>
-          <% assignments = wf.next_assignments(file.last_revision.id) %>
-          <% index = assignments.find_index{|assignment| assignment.user_id == User.current.id} if assignments %>
-          <% if index %>
-            <%= link_to('',
-              action_dmsf_workflow_path(
-                  :project_id => project.id,
-                  :id => wf.id,
-                  :dmsf_workflow_step_assignment_id => assignments[index].id,
-                  :dmsf_file_revision_id => file.last_revision.id),
-              :title => l(:title_waiting_for_approval),
-              :remote => true,
-              :class => 'icon icon-wf-waiting') %>
-          <% end %>
-        <% end %>
-      <% when DmsfWorkflow::STATE_ASSIGNED %>
-        <% if User.current && (file.last_revision.dmsf_workflow_assigned_by == User.current.id) && wf %>
-          <%= link_to('',
-            start_dmsf_workflow_path(
-                :id => file.last_revision.dmsf_workflow_id,
-                :dmsf_file_revision_id => file.last_revision.id),
-            :title => l(:label_dmsf_wokflow_action_start),
-            :class => 'icon icon-wf-assigned') %>
-        <% end %>
-      <% when DmsfWorkflow::STATE_APPROVED, DmsfWorkflow::STATE_REJECTED %>
-      <% else %>
-        <% if @workflows_available %>
-          <%= link_to('',
-            assign_dmsf_workflow_path(
-                :project_id => project.id,
-                :dmsf_file_revision_id => file.last_revision.id),
-            :title => l(:label_dmsf_wokflow_action_assign),
-            :remote => true,
-            :class => 'icon icon-wf-none') %>
-        <% end %>
-    <% end %>
-  <% end %>
+  <%= render(:partial => 'dmsf_files/approval_workflow_button',
+    :locals => {:file => file, :file_approval_allowed => @file_approval_allowed,
+                :workflows_available => @workflows_available, :project => project, :wf => wf }) %>
 </td>
 <td class="hol"><%= position %></td>
 <td class="hol"><%= file.last_revision.size %></td>
diff --git a/app/views/dmsf/_list_view.erb b/app/views/dmsf/_list_view.erb
index 49678603..499d0463 100644
--- a/app/views/dmsf/_list_view.erb
+++ b/app/views/dmsf/_list_view.erb
@@ -65,7 +65,7 @@
   </thead>
   <tbody>
   <% @subfolders.each do |subfolder| %>
-    <tr class="dir">
+    <tr class="dir <%= 'dmsf_system' if subfolder.system %>">
       <%= render(:partial => 'dir',
         :locals => {
           :project => @project,
diff --git a/app/views/dmsf/edit.html.erb b/app/views/dmsf/edit.html.erb
index efcb47f9..95bc1893 100644
--- a/app/views/dmsf/edit.html.erb
+++ b/app/views/dmsf/edit.html.erb
@@ -25,7 +25,7 @@
 <% html_title(l(:dmsf)) %>
 
 <div class="contextual">
-  <% if !@folder.new_record? && User.current.allowed_to?(:folder_manipulation, @project) %>
+  <% if !@folder.new_record? && User.current.allowed_to?(:folder_manipulation, @project) && !@folder.system %>
     <% unless @folder.locked? %>
       <%= link_to(l(:button_lock), lock_dmsf_path(:id => @project, :folder_id => @folder),
         :title => l(:title_lock_file), :class => 'icon icon-lock') %>
diff --git a/app/views/dmsf/show.html.erb b/app/views/dmsf/show.html.erb
index 3a0cffea..6627cc60 100644
--- a/app/views/dmsf/show.html.erb
+++ b/app/views/dmsf/show.html.erb
@@ -24,7 +24,7 @@
 
 <% html_title l(:dmsf) %>
 <div class="contextual">
-  <% if @folder_manipulation_allowed %>
+  <% if @folder_manipulation_allowed && !@system_folder %>
     <% if @folder.nil? %>
       <%= link_to(l(:button_edit), edit_root_dmsf_path(:id => @project),
         :title => l(:link_edit, :title => l(:link_documents)),
@@ -92,16 +92,18 @@
         <%= submit_tag(l(:button_delete), :title => l(:title_delete_checked), :name => 'delete_entries') if @file_delete_allowed %>
     <% end %>
   </div>
-  <% values = @folder ? @folder.custom_field_values : DmsfFolder.new.custom_field_values %>
-  <% unless values.empty? %>
-    <div id="dmsf_tag" class="dmsf_controls" style="float: right">
-      <% custom_value = values.first %>
-      <% custom_value.custom_field.is_required = false %>
-      <% custom_value.value = params[:custom_value].present? ? params[:custom_value] : '' %>
-      <% name = :dmsf_folder %>
-      <%= content_tag('label', custom_field_name_tag(custom_value.custom_field),
-            :for => "#{name}_custom_field_values_#{custom_value.custom_field.id}") + ': ' + custom_field_tag(name, custom_value) %>
-    </div>
+  <% unless @system_folder %>
+    <% values = @folder ? @folder.custom_field_values : DmsfFolder.new.custom_field_values %>
+    <% unless values.empty? %>
+      <div id="dmsf_tag" class="dmsf_controls" style="float: right">
+        <% custom_value = values.first %>
+        <% custom_value.custom_field.is_required = false %>
+        <% custom_value.value = params[:custom_value].present? ? params[:custom_value] : '' %>
+        <% name = :dmsf_folder %>
+        <%= content_tag('label', custom_field_name_tag(custom_value.custom_field),
+              :for => "#{name}_custom_field_values_#{custom_value.custom_field.id}") + ': ' + custom_field_tag(name, custom_value) %>
+      </div>
+    <% end %>
   <% end %>
   <div class="autoscroll">
     <% if @tree_view %>
@@ -181,7 +183,7 @@
             <% if @folder %>
               return "<%= "#{l(:label_number_of_folders)}: #{@folder.deep_folder_count} #{l(:label_number_of_documents)}: #{@folder.deep_file_count}" %>";
             <% else %>
-              return "<%= "#{l(:label_number_of_folders)}: #{DmsfFolder.visible.where(:project_id => @project.id).count + DmsfLink.visible.where(:project_id => @project.id, :target_type => 'DmsfFolder').count}, #{l(:label_number_of_documents)}: #{DmsfFile.visible.where(:container_id => @project.id, :container_type => 'Project').count + DmsfLink.visible.where(:project_id => @project.id, :target_type => 'DmsfFile').count + DmsfLink.visible.where(:project_id => @project.id, :target_type => 'DmsfUrl').count}" %>";
+              return "<%= "#{l(:label_number_of_folders)}: #{DmsfFolder.visible.where(:project_id => @project.id).count + DmsfLink.visible.where(:project_id => @project.id, :target_type => 'DmsfFolder').count}, #{l(:label_number_of_documents)}: #{DmsfFile.visible.where(:project_id => @project.id).count + DmsfLink.visible.where(:project_id => @project.id, :target_type => ['DmsfFile', 'DmsfUrl']).count}" %>";
             <% end %>
           <% else %>
             return "<%= "#{l(:label_number_of_folders)}: #{@subfolders.count + @dir_links.count}, #{l(:label_number_of_documents)}: #{@files.count + @file_links.count + @url_links.count}" %>";
@@ -207,12 +209,14 @@
   </script>
 <% end %>
 
-<% if (@file_manipulation_allowed && !@locked_for_user) %>
+<% if (@file_manipulation_allowed && !@locked_for_user && !@system_folder) %>
   <%= render(:partial => 'dmsf_upload/multi_upload') %>
 <% end %>
 
-<% other_formats_links do |f| %>
+<% unless @system_folder %>
+  <% other_formats_links do |f| %>
     <%= f.link_to 'CSV', :url => params, :onclick => "showModal('csv-export-options', '350px'); return false;" %>
+  <% end %>
 <% end %>
 
 <div id="csv-export-options" style="display:none;">
diff --git a/app/views/dmsf_files/_approval_workflow_button.html.erb b/app/views/dmsf_files/_approval_workflow_button.html.erb
new file mode 100644
index 00000000..f23fb74b
--- /dev/null
+++ b/app/views/dmsf_files/_approval_workflow_button.html.erb
@@ -0,0 +1,62 @@
+<%
+  # encoding: utf-8
+  #
+  # Redmine plugin for Document Management System "Features"
+  #
+  # Copyright (C) 2011-17 Karel Pičman <karel.picman@kontron.com>
+  #
+  # This program is free software; you can redistribute it and/or
+  # modify it under the terms of the GNU General Public License
+  # as published by the Free Software Foundation; either version 2
+  # of the License, or (at your option) any later version.
+  #
+  # This program is distributed in the hope that it will be useful,
+  # but WITHOUT ANY WARRANTY; without even the implied warranty of
+  # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+  # GNU General Public License for more details.
+  #
+  # You should have received a copy of the GNU General Public License
+  # along with this program; if not, write to the Free Software
+  # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+%>
+
+<% if file_approval_allowed %>
+  <% case file.last_revision.workflow %>
+    <% when DmsfWorkflow::STATE_WAITING_FOR_APPROVAL %>
+        <% if wf %>
+            <% assignments = wf.next_assignments(file.last_revision.id) %>
+            <% index = assignments.find_index{|assignment| assignment.user_id == User.current.id} if assignments %>
+            <% if index %>
+                <%= link_to('',
+                            action_dmsf_workflow_path(
+                                :project_id => project.id,
+                                :id => wf.id,
+                                :dmsf_workflow_step_assignment_id => assignments[index].id,
+                                :dmsf_file_revision_id => file.last_revision.id),
+                            :title => l(:title_waiting_for_approval),
+                            :remote => true,
+                            :class => 'icon icon-wf-waiting') %>
+            <% end %>
+        <% end %>
+    <% when DmsfWorkflow::STATE_ASSIGNED %>
+        <% if User.current && (file.last_revision.dmsf_workflow_assigned_by == User.current.id) && wf %>
+            <%= link_to('',
+                        start_dmsf_workflow_path(
+                            :id => file.last_revision.dmsf_workflow_id,
+                            :dmsf_file_revision_id => file.last_revision.id),
+                        :title => l(:label_dmsf_wokflow_action_start),
+                        :class => 'icon icon-wf-assigned') %>
+        <% end %>
+    <% when DmsfWorkflow::STATE_APPROVED, DmsfWorkflow::STATE_REJECTED %>
+    <% else %>
+        <% if workflows_available %>
+            <%= link_to('',
+                        assign_dmsf_workflow_path(
+                            :project_id => project.id,
+                            :dmsf_file_revision_id => file.last_revision.id),
+                        :title => l(:label_dmsf_wokflow_action_assign),
+                        :remote => true,
+                        :class => 'icon icon-wf-none') %>
+        <% end %>
+    <% end %>
+<% end %>
\ No newline at end of file
diff --git a/app/views/dmsf_files/_links.html.erb b/app/views/dmsf_files/_links.html.erb
index 33872282..1b928310 100644
--- a/app/views/dmsf_files/_links.html.erb
+++ b/app/views/dmsf_files/_links.html.erb
@@ -22,7 +22,7 @@
 
 <% if dmsf_files.present? %>
   <hr/>
-  <div class="attachments">
+  <div class="attachments dmsf_parent_container">
     <% for dmsf_file in dmsf_files %>
         <% if dmsf_file.last_revision %>
           <p>
@@ -50,6 +50,14 @@
                 :class => 'icon icon-del') %>
             <% end %>
             <span class="author"><%= dmsf_file.last_revision.user %>, <%= format_time(dmsf_file.last_revision.updated_at) %></span>
+            <span class="dmsf_upload_select">
+              <% wf = DmsfWorkflow.find_by_id(dmsf_file.last_revision.dmsf_workflow_id) if dmsf_file.last_revision.dmsf_workflow_id %>
+              <%= render(:partial => 'dmsf_files/approval_workflow_button',
+                :locals => {:file => dmsf_file,
+                   :file_approval_allowed => User.current.allowed_to?(:file_approval, dmsf_file.project),
+                   :workflows_available => DmsfWorkflow.where(['project_id = ? OR project_id IS NULL', dmsf_file.project.id]).exists?,
+                   :project => dmsf_file.project, :wf => wf }) %>
+            </span>
           </p>
         <% end %>
     <% end %>
diff --git a/app/views/dmsf_files/show.api.rsb b/app/views/dmsf_files/show.api.rsb
index dc192c53..f998adce 100644
--- a/app/views/dmsf_files/show.api.rsb
+++ b/app/views/dmsf_files/show.api.rsb
@@ -1,8 +1,7 @@
 api.dmsf_file do
   api.id @file.id
   api.name @file.name
-  api.container_id @file.container_id
-  api.container_type @file.container_type
+  api.project_id @file.project_id
   api.dmsf_folder_id @file.folder if @file.dmsf_folder_id
   api.version "#{@file.last_revision.major_version}.#{@file.last_revision.minor_version}" if @file.last_revision
   api.content_url url_for(:controller => :dmsf_files, :action => 'show', :download => '', :id => @file)
diff --git a/app/views/dmsf_files/show.html.erb b/app/views/dmsf_files/show.html.erb
index 0239d078..73c2dc14 100644
--- a/app/views/dmsf_files/show.html.erb
+++ b/app/views/dmsf_files/show.html.erb
@@ -152,10 +152,8 @@
           <div class="status attribute">
             <%= content_tag :div, l(:label_file), :class => 'label' %>
             <div class="value">
-              <% if revision.dmsf_file.dmsf_folder %>
-                <%= (h("#{revision.dmsf_file.dmsf_folder.dmsf_path_str}/")) %>
-              <% end %>
-              <%= h(revision.name) %>
+              <% path = "#{revision.dmsf_file.dmsf_folder.dmsf_path_str}/" if revision.dmsf_file.dmsf_folder %>
+              <%= h("#{path}#{revision.name}") %>
             </div>
           </div>
           <div class="status attribute">
diff --git a/app/views/settings/_dmsf_settings.html.erb b/app/views/settings/_dmsf_settings.html.erb
index 719c4f6d..cb248e8b 100644
--- a/app/views/settings/_dmsf_settings.html.erb
+++ b/app/views/settings/_dmsf_settings.html.erb
@@ -137,6 +137,15 @@
   </em>
 </p>
 
+<p>
+  <%= content_tag(:label, l(:label_show_system_folders)) %>
+  <%= check_box_tag('settings[dmsf_show_system_folders]', true, @settings['dmsf_show_system_folders']) %>
+  <em class="info">
+    <%= l(:note_dmsf_show_system_folders) %><br/>
+    <%= l(:label_default)%>: <%= l(:general_text_No)%>
+  </em>
+</p>
+
 <hr/>
 <em class="info">
   <%= l(:menu_dmsf) %> <%= l(:field_column_names) %>
diff --git a/assets/images/folder_system.png b/assets/images/folder_system.png
new file mode 100644
index 00000000..8e43710b
Binary files /dev/null and b/assets/images/folder_system.png differ
diff --git a/assets/stylesheets/redmine_dmsf.css b/assets/stylesheets/redmine_dmsf.css
index aa45572c..8b698faa 100644
--- a/assets/stylesheets/redmine_dmsf.css
+++ b/assets/stylesheets/redmine_dmsf.css
@@ -194,6 +194,7 @@ div.dmsf_revision_inner_box .attribute .label {
 
 /* File types */
 .dmsf_gray .icon-folder { background-image: url(../images/folder_gray.png); }
+.dmsf_system .icon-folder { background-image: url(../images/folder_system.png); }
 
 .icon-file.filetype-doc, .icon-file.filetype-docx { background-image: url(../images/filetypes/doc.png); }
 .icon-file.filetype-xls, .icon-file.filetype-xlsx { background-image: url(../images/filetypes/xls.png); }
@@ -240,6 +241,10 @@ div.dmsf_revision_inner_box .attribute .label {
 .dmsf_gray { color: #AAA }
 .dmsf_gray a, .dmsf_gray a:link, .dmsf_gray a:visited{ color: #484848; text-decoration: none; }
 
+/* System folders */
+.dmsf_system { color: #5C82AD }
+.dmsf_system a, .dmsf_gray a:link, .dmsf_gray a:visited{ color: #484848; text-decoration: none; }
+
 /* Search results */
 .dmsf-file { background-image: url(../../../images/document.png); }
 .dmsf-folder { background-image: url(../../../images/folder.png); }
diff --git a/config/locales/cs.yml b/config/locales/cs.yml
index af851c6e..3c0dac75 100644
--- a/config/locales/cs.yml
+++ b/config/locales/cs.yml
@@ -363,5 +363,7 @@ cs:
 
   label_act_as_attachable: Jako příloha
   note_dmsf_act_as_attachable: Umožní přikládat dokumenty k objektům např. úkolům.
+  label_show_system_folders: Zobrazit systémové složky
+  note_dmsf_show_system_folders: Systémové složky jsou složky se specifickým určením, např. pro dokumenty nahrané k úkolům.
 
   label_user_search_add: Vyhledej uživatele pro přidání
\ No newline at end of file
diff --git a/config/locales/de.yml b/config/locales/de.yml
index aedc141e..914f51c1 100644
--- a/config/locales/de.yml
+++ b/config/locales/de.yml
@@ -360,5 +360,7 @@ de:
 
   label_act_as_attachable: Act as attachable
   note_dmsf_act_as_attachable: Allows to attach documents to objects e.g. issues.
+  label_show_system_folders: Show system folders
+  note_dmsf_show_system_folders: System folders are folders with a specifics purpose, e.g. for documents attached to issues.
 
   label_user_search_add: Search for user to add
\ No newline at end of file
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 7e15adbf..c9021032 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -363,5 +363,7 @@ en:
 
   label_act_as_attachable: Act as attachable
   note_dmsf_act_as_attachable: Allows to attach documents to objects e.g. issues.
+  label_show_system_folders: Show system folders
+  note_dmsf_show_system_folders: System folders are folders with a specifics purpose, e.g. for documents attached to issues.
 
   label_user_search_add: Search for user to add
diff --git a/config/locales/es.yml b/config/locales/es.yml
index a37391fb..5dd346a9 100644
--- a/config/locales/es.yml
+++ b/config/locales/es.yml
@@ -363,5 +363,7 @@ es:
 
   label_act_as_attachable: Act as attachable
   note_dmsf_act_as_attachable: Allows to attach documents to objects e.g. issues.
+  label_show_system_folders: Show system folders
+  note_dmsf_show_system_folders: System folders are folders with a specifics purpose, e.g. for documents attached to issues.
 
   label_user_search_add: Search for user to add
\ No newline at end of file
diff --git a/config/locales/fr.yml b/config/locales/fr.yml
index df5f8aba..320435c7 100644
--- a/config/locales/fr.yml
+++ b/config/locales/fr.yml
@@ -363,5 +363,7 @@ fr:
 
   label_act_as_attachable: Act as attachable
   note_dmsf_act_as_attachable: Allows to attach documents to objects e.g. issues.
+  label_show_system_folders: Show system folders
+  note_dmsf_show_system_folders: System folders are folders with a specifics purpose, e.g. for documents attached to issues.
 
   label_user_search_add: Search for user to add
\ No newline at end of file
diff --git a/config/locales/hu.yml b/config/locales/hu.yml
index 61592d9f..709ebb5e 100644
--- a/config/locales/hu.yml
+++ b/config/locales/hu.yml
@@ -362,5 +362,7 @@ hu:
 
   label_act_as_attachable: Act as attachable
   note_dmsf_act_as_attachable: Allows to attach documents to objects e.g. issues.
+  label_show_system_folders: Show system folders
+  note_dmsf_show_system_folders: System folders are folders with a specifics purpose, e.g. for documents attached to issues.
 
   label_user_search_add: Search for user to add
\ No newline at end of file
diff --git a/config/locales/it.yml b/config/locales/it.yml
index 780dac70..62eca1ce 100644
--- a/config/locales/it.yml
+++ b/config/locales/it.yml
@@ -363,5 +363,7 @@ it: # Italian strings thx 2 Matteo Arceci!
 
   label_act_as_attachable: Act as attachable
   note_dmsf_act_as_attachable: Allows to attach documents to objects e.g. issues.
+  label_show_system_folders: Show system folders
+  note_dmsf_show_system_folders: System folders are folders with a specifics purpose, e.g. for documents attached to issues.
 
   label_user_search_add: Search for user to add
\ No newline at end of file
diff --git a/config/locales/ja.yml b/config/locales/ja.yml
index 684bde65..aea56677 100644
--- a/config/locales/ja.yml
+++ b/config/locales/ja.yml
@@ -363,5 +363,7 @@ ja:
 
   label_act_as_attachable: Act as attachable
   note_dmsf_act_as_attachable: Allows to attach documents to objects e.g. issues.
+  label_show_system_folders: Show system folders
+  note_dmsf_show_system_folders: System folders are folders with a specifics purpose, e.g. for documents attached to issues.
 
   label_user_search_add: Search for user to add
\ No newline at end of file
diff --git a/config/locales/pl.yml b/config/locales/pl.yml
index cd88945d..65d40a65 100644
--- a/config/locales/pl.yml
+++ b/config/locales/pl.yml
@@ -363,5 +363,7 @@ pl:
 
   label_act_as_attachable: Act as attachable
   note_dmsf_act_as_attachable: Allows to attach documents to objects e.g. issues.
+  label_show_system_folders: Show system folders
+  note_dmsf_show_system_folders: System folders are folders with a specifics purpose, e.g. for documents attached to issues.
 
   label_user_search_add: Search for user to add
\ No newline at end of file
diff --git a/config/locales/pt-BR.yml b/config/locales/pt-BR.yml
index 71e1ab01..7e2d86fc 100644
--- a/config/locales/pt-BR.yml
+++ b/config/locales/pt-BR.yml
@@ -363,5 +363,7 @@ pt-BR:
 
   label_act_as_attachable: Act as attachable
   note_dmsf_act_as_attachable: Allows to attach documents to objects e.g. issues.
+  label_show_system_folders: Show system folders
+  note_dmsf_show_system_folders: System folders are folders with a specifics purpose, e.g. for documents attached to issues.
 
   label_user_search_add: Search for user to add
\ No newline at end of file
diff --git a/config/locales/ru.yml b/config/locales/ru.yml
index c61ab12f..bae508a5 100644
--- a/config/locales/ru.yml
+++ b/config/locales/ru.yml
@@ -363,5 +363,7 @@ ru:
 
   label_act_as_attachable: Act as attachable
   note_dmsf_act_as_attachable: Allows to attach documents to objects e.g. issues.
+  label_show_system_folders: Show system folders
+  note_dmsf_show_system_folders: System folders are folders with a specifics purpose, e.g. for documents attached to issues.
 
   label_user_search_add: Search for user to add
\ No newline at end of file
diff --git a/config/locales/sl.yml b/config/locales/sl.yml
index ab63a887..0d2d504a 100644
--- a/config/locales/sl.yml
+++ b/config/locales/sl.yml
@@ -363,5 +363,7 @@ sl:
 
   label_act_as_attachable: Act as attachable
   note_dmsf_act_as_attachable: Allows to attach documents to objects e.g. issues.
+  label_show_system_folders: Show system folders
+  note_dmsf_show_system_folders: System folders are folders with a specifics purpose, e.g. for documents attached to issues.
 
   label_user_search_add: Search for user to add
\ No newline at end of file
diff --git a/config/locales/zh-TW.yml b/config/locales/zh-TW.yml
index 02452bda..0746d8b4 100644
--- a/config/locales/zh-TW.yml
+++ b/config/locales/zh-TW.yml
@@ -363,5 +363,7 @@ zh-TW:
 
   label_act_as_attachable: Act as attachable
   note_dmsf_act_as_attachable: Allows to attach documents to objects e.g. issues.
+  label_show_system_folders: Show system folders
+  note_dmsf_show_system_folders: System folders are folders with a specifics purpose, e.g. for documents attached to issues.
 
   label_user_search_add: Search for user to add
\ No newline at end of file
diff --git a/config/locales/zh.yml b/config/locales/zh.yml
index 8e10f060..7ec776a2 100644
--- a/config/locales/zh.yml
+++ b/config/locales/zh.yml
@@ -363,5 +363,7 @@ zh:
 
   label_act_as_attachable: Act as attachable
   note_dmsf_act_as_attachable: Allows to attach documents to objects e.g. issues.
+  label_show_system_folders: Show system folders
+  note_dmsf_show_system_folders: System folders are folders with a specifics purpose, e.g. for documents attached to issues.
 
   label_user_search_add: Search for user to add
\ No newline at end of file
diff --git a/db/migrate/20170421101901_dmsf_file_container_rollback.rb b/db/migrate/20170421101901_dmsf_file_container_rollback.rb
new file mode 100644
index 00000000..d3ab16b9
--- /dev/null
+++ b/db/migrate/20170421101901_dmsf_file_container_rollback.rb
@@ -0,0 +1,85 @@
+# encoding: utf-8
+#
+# Redmine plugin for Document Management System "Features"
+#
+# Copyright (C) 2011-17 Karel Pičman <karel.picman@kontron.com>
+#
+# This program is free software; you can redistribute it and/or
+# modify it under the terms of the GNU General Public License
+# as published by the Free Software Foundation; either version 2
+# of the License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
+class DmsfFileContainerRollback < ActiveRecord::Migration
+  def up
+    # Create necessary folders
+    new_folder_ids = []
+    description = 'Documents assigned to issues'
+    DmsfFile.where(:container_type => 'Issue').each do |file|
+      issue = Issue.find_by_id file.container_id
+      unless issue
+        Rails.logger.error "Issue ##{file.container_id} not found"
+        next
+      end
+      # Parent folder
+      parent = DmsfFolder.where(:project_id => issue.project.id, :title => '.Issues', :description => description).first
+      unless parent
+        parent = DmsfFolder.new
+        parent.project_id = issue.project.id
+        parent.title = '.Issues'
+        parent.description = description
+        parent.user_id = User.anonymous.id
+        parent.save
+        new_folder_ids << parent.id
+      end
+      # Issue folder
+      folder = DmsfFolder.new
+      folder.project_id = issue.project.id
+      folder.dmsf_folder_id = parent.id
+      folder.title = "#{issue.id} - #{issue.subject}"
+      folder.user_id = User.anonymous.id
+      folder.save
+      new_folder_ids << folder.id
+      # Move the file into the new folder
+      file.dmsf_folder_id = folder.id
+      file.save
+    end
+    # Make DB changes in dmsf_files
+    remove_index :dmsf_files, [:container_id, :container_type]
+    remove_column :dmsf_files, :container_type
+    rename_column :dmsf_files, :container_id, :project_id
+    add_index :dmsf_files, :project_id
+    # Add system folder_flag to dmsf_folders
+    add_column :dmsf_folders, :system, :boolean, :null => false, :default => false
+    DmsfFolder.where(:id => new_folder_ids).update_all(:system => true)
+  end
+
+  def down
+    # dmsf_files
+    file_folder_ids = DmsfFile.joins(:dmsf_folder).where('dmsf_folders.system = 1').pluck('dmsf_files.id, cast(dmsf_folders.title as unsigned)')
+    remove_index :dmsf_files, :project_id
+    rename_column :dmsf_files, :project_id, :container_id
+    add_column :dmsf_files, :container_type, :string, :limit => 30, :null => false, :default => 'Project'
+    DmsfFile.update_all(:container_type => 'Project')
+    file_folder_ids.each do |id, container_id|
+      file = DmsfFile.find_by_id(id)
+      if file
+        file.container_id = container_id
+        file.container_type = 'Issue'
+        file.save
+      end
+    end
+    add_index :dmsf_files, [:container_id, :container_type]
+    # dmsf_folders
+    DmsfFolder.where(:system => true).delete_all
+    remove_column :dmsf_folders, :system
+  end
+end
diff --git a/init.rb b/init.rb
index 5646ad12..61b182b0 100644
--- a/init.rb
+++ b/init.rb
@@ -52,7 +52,8 @@ Redmine::Plugin.register :redmine_dmsf do
               'dmsf_webdav_ignore' => '^(\._|\.DS_Store$|Thumbs.db$)',
               'dmsf_webdav_disable_versioning' => '^\~\$|\.tmp$',
               'dmsf_keep_documents_locked' => false,
-              'dmsf_act_as_attachable' => false
+              'dmsf_act_as_attachable' => false,
+              'dmsf_show_system_folders' => false
             }
   
   menu :project_menu, :dmsf, { :controller => 'dmsf', :action => 'show' }, :caption => :menu_dmsf, :before => :documents, :param => :id
diff --git a/lib/redmine_dmsf/hooks/controllers/issues_controller_hooks.rb b/lib/redmine_dmsf/hooks/controllers/issues_controller_hooks.rb
index 2577c68a..bfd8a79e 100644
--- a/lib/redmine_dmsf/hooks/controllers/issues_controller_hooks.rb
+++ b/lib/redmine_dmsf/hooks/controllers/issues_controller_hooks.rb
@@ -33,8 +33,8 @@ module RedmineDmsf
           copied_from = Issue.find_by_id(params[:copy_from]) if params[:copy_from].present?
           # Save documents
           if copied_from
-            issue.dmsf_files = copied_from.dmsf_files.map do |dmsf_file|
-              dmsf_file.copy_to(issue)
+            copied_from.dmsf_files.each do |dmsf_file|
+              dmsf_file.copy_to(issue.project, issue.system_folder(true))
             end
           end
         end
@@ -53,14 +53,15 @@ module RedmineDmsf
           params = context[:params]
           uploaded_files = params[:dmsf_attachments]
           if uploaded_files && uploaded_files.is_a?(Hash)
-            # standard file input uploads
+            system_folder = issue.system_folder(true)
             uploaded_files.each_value do |uploaded_file|
-              upload = DmsfUpload.create_from_uploaded_attachment(issue.project, nil, uploaded_file)
+              upload = DmsfUpload.create_from_uploaded_attachment(issue.project, system_folder, uploaded_file)
               uploaded_file[:disk_filename] = upload.disk_filename
               uploaded_file[:name] = upload.name
               uploaded_file[:title] = upload.title
             end
-            DmsfUploadHelper.commit_files_internal uploaded_files, issue, nil, context[:controller]
+            DmsfUploadHelper.commit_files_internal uploaded_files, issue.project, system_folder,
+             context[:controller]
           end
         end
       end
diff --git a/lib/redmine_dmsf/patches/issue_patch.rb b/lib/redmine_dmsf/patches/issue_patch.rb
index 599b3c62..3284bad4 100644
--- a/lib/redmine_dmsf/patches/issue_patch.rb
+++ b/lib/redmine_dmsf/patches/issue_patch.rb
@@ -26,20 +26,47 @@ module RedmineDmsf
         base.send(:include, InstanceMethods)
         base.class_eval do
           unloadable
-          alias_method_chain :copy_from, :dmsf_copy_from
-          has_many :dmsf_files, -> { where(dmsf_folder_id: nil, container_type: 'Issue').order(:name) },
-            :class_name => 'DmsfFile', :foreign_key => 'container_id', :dependent => :destroy
+          before_destroy :delete_system_folder
         end
       end
 
       module InstanceMethods
 
-        def copy_from_with_dmsf_copy_from(arg, options={})
-          copy_from_without_dmsf_copy_from(arg, options)
-          # issue = @copied_from
-          # self.dmsf_files = issue.dmsf_files.map do |dmsf_file|
-          #   dmsf_file.copy_to(self)
-          # end
+        def system_folder(create = false)
+          parent = DmsfFolder.system.where(:project_id => self.project_id, :title => '.Issues').first
+          if create && !parent
+            parent = DmsfFolder.new
+            parent.project_id = self.project_id
+            parent.title = '.Issues'
+            parent.description = 'Documents assigned to issues'
+            parent.user_id = User.anonymous.id
+            parent.system = true
+            parent.save
+          end
+          if parent
+            folder = DmsfFolder.system.where(['project_id = ? AND dmsf_folder_id = ? AND CAST(title AS UNSIGNED) = ?',
+              self.project_id, parent.id, self.id]).first
+            if create && !folder
+              folder = DmsfFolder.new
+              folder.dmsf_folder_id = parent.id
+              folder.project_id = self.project_id
+              folder.title = "#{self.id} - #{self.subject}"
+              folder.user_id = User.anonymous.id
+              folder.system = true
+              folder.save
+            end
+          end
+          folder
+        end
+
+        def dmsf_files
+          folder = self.system_folder
+          folder.dmsf_files if folder
+        end
+
+        def delete_system_folder
+          folder = self.system_folder
+          folder.destroy if folder
         end
 
         def dmsf_file_added(dmsf_file)
diff --git a/lib/redmine_dmsf/patches/project_patch.rb b/lib/redmine_dmsf/patches/project_patch.rb
index 579dd507..77318b21 100644
--- a/lib/redmine_dmsf/patches/project_patch.rb
+++ b/lib/redmine_dmsf/patches/project_patch.rb
@@ -31,11 +31,10 @@ module RedmineDmsf
           unloadable
           alias_method_chain :copy, :dmsf
 
-          has_many :dmsf_files, -> { where(dmsf_folder_id: nil, container_type: 'Project').order(:name) },
-            :class_name => 'DmsfFile', :foreign_key => 'container_id', :dependent => :destroy
-          has_many :dmsf_folders, -> { where(dmsf_folder_id: nil).order(:title) },
-            :class_name => 'DmsfFolder', :foreign_key => 'project_id',
-            :dependent => :destroy
+          has_many :dmsf_files, -> { where(dmsf_folder_id: nil).order(:name) },
+            :class_name => 'DmsfFile', :foreign_key => 'project_id', :dependent => :destroy
+          has_many :dmsf_folders, ->{ where(:dmsf_folder_id => nil).order(:title) },
+            :class_name => 'DmsfFolder', :foreign_key => 'project_id', :dependent => :destroy
           has_many :dmsf_workflows, :dependent => :destroy
           has_many :folder_links, -> { where dmsf_folder_id: nil, target_type: 'DmsfFolder' },
             :class_name => 'DmsfLink', :foreign_key => 'project_id', :dependent => :destroy
diff --git a/lib/redmine_dmsf/webdav/controller.rb b/lib/redmine_dmsf/webdav/controller.rb
index eaff479b..f2fa8f8e 100644
--- a/lib/redmine_dmsf/webdav/controller.rb
+++ b/lib/redmine_dmsf/webdav/controller.rb
@@ -210,10 +210,10 @@ module RedmineDmsf
               # File
               # Use file.id & file.last_revision.id as key
               # When revision changes then the key will change and the old cached item will eventually be evicted
-              propstats_key = "PROPSTATS/#{resource.resource.file.id}-#{resource.resource.file.last_revision.id}"
+              propstats_key = "PROPSTATS/#{resource.resource.file.id}-#{resource.resource.file.last_revision.id}" if resource.resource.file
             end
 
-            xml_str = RedmineDmsf::Webdav::Cache.read(propstats_key)
+            xml_str = RedmineDmsf::Webdav::Cache.read(propstats_key) if propstats_key
             if xml_str.nil?
               # Create the complete PROPSTATS response
               propstats_builder = Nokogiri::XML::Builder.new do |propstats_xml|
@@ -238,7 +238,7 @@ module RedmineDmsf
               
               # Add PROPSTATS to cache
               # Caching the PROPSTATS response as xml text string.
-              RedmineDmsf::Webdav::Cache.write(propstats_key, xml_str)
+              RedmineDmsf::Webdav::Cache.write(propstats_key, xml_str) if propstats_key
             end
             xml << xml_str
           end
diff --git a/lib/redmine_dmsf/webdav/dmsf_resource.rb b/lib/redmine_dmsf/webdav/dmsf_resource.rb
index ba878bce..50099e7f 100644
--- a/lib/redmine_dmsf/webdav/dmsf_resource.rb
+++ b/lib/redmine_dmsf/webdav/dmsf_resource.rb
@@ -88,50 +88,21 @@ module RedmineDmsf
       # Check if current entity is a folder and return DmsfFolder object if found (nil if not)
       def folder
         unless @folder
-          return nil unless project # If the project doesn't exist, this entity can't exist
-          # Note: Folder is searched for as a generic search to prevent SQL queries being generated:
-          # if we were to look within parent, we'd have to go all the way up the chain as part of the
-          # existence check, and although I'm sure we'd love to access the hierarchy, I can't yet
-          # see a practical need for it
-          folders = DmsfFolder.visible.where(:project_id => project.id, :title => basename).order('title ASC').to_a
-          return nil unless folders.length > 0
-          if (folders.length > 1)
-            folders.delete_if { |x| '/' + x.dmsf_path_str != projectless_path }
-            return nil unless folders.length > 0
-            @folder = folders[0]
-          else
-            if (('/' + folders[0].dmsf_path_str) == projectless_path)
-              @folder = folders[0]
-            end
-          end
+          return nil unless project
+          f = parent.folder
+          @folder = DmsfFolder.visible.where(:project_id => project.id, :title => basename,
+            :dmsf_folder_id => parent.folder ? parent.folder.id : nil).first
         end
         @folder
       end
 
       # Check if current entity exists as a file (DmsfFile), and returns corresponding object if found (nil otherwise)
-      # Currently has a dual search approach (depending on if parent can be determined)
       def file
         unless @file
           return nil unless project # Again if entity project is nil, it cannot exist in context of this object
-          # Hunt for files parent path
-          f = false
-          if (parent.projectless_path != '/')
-            f = parent.folder if parent.folder
-          else
-            f = nil
-          end
-          if f || f.nil?
-            # f has a value other than false? - lets use traditional
-            # DMSF file search by name.
-            @file = DmsfFile.visible.find_file_by_name(project, f, basename)
-          else
-            # If folder is false, means it couldn't pick up parent,
-            # as such its probably fine to bail out, however we'll
-            # perform a search in this scenario
-            files = DmsfFile.visible.where(:container_id => project.id, :container_type => 'Project', :name => basename).order('name ASC').to_a
-            files.delete_if { |x| File.dirname('/' + x.dmsf_path_str) != File.dirname(projectless_path) }
-            @file = files[0] if files.length > 0
-          end
+          @file = DmsfFile.visible.joins('JOIN dmsf_file_revisions ON dmsf_files.id = dmsf_file_revisions.dmsf_file_id').where(
+            ["dmsf_files.project_id = ? AND dmsf_files.dmsf_folder_id #{parent.folder ? '=' : 'IS'} ? AND dmsf_file_revisions.name = ?",
+             project.id, parent.folder ? parent.folder.id : nil, basename]).first
         end
         @file
       end
@@ -189,6 +160,7 @@ module RedmineDmsf
       ##
       def get(request, response)
         raise NotFound unless exist?
+        raise Forbidden unless (!parent.exist? || !parent.folder || DmsfFolder.permissions?(parent.folder))
         if collection?
           html_display
           response['Content-Length'] = response.body.bytesize.to_s
@@ -207,6 +179,7 @@ module RedmineDmsf
         if request.body.read.to_s.empty?
           raise NotFound unless project && project.module_enabled?('dmsf')
           raise Forbidden unless User.current.admin? || User.current.allowed_to?(:folder_manipulation, project)
+          raise Forbidden unless (!parent.exist? || !parent.folder || DmsfFolder.permissions?(parent.folder, false))
           return MethodNotAllowed if exist? # If we already exist, why waste the time trying to save?
           parent_folder = nil
           if (parent.projectless_path != '/')
@@ -231,7 +204,7 @@ module RedmineDmsf
       def delete
         if file
           raise Forbidden unless User.current.admin? || User.current.allowed_to?(:file_delete, project)
-          
+          raise Forbidden unless (!parent.exist? || !parent.folder || DmsfFolder.permissions?(parent.folder, false))
           pattern = Setting.plugin_redmine_dmsf['dmsf_webdav_disable_versioning']
           if !pattern.blank? && basename.match(pattern)
             # Files that are not versioned should be destroyed
@@ -253,6 +226,7 @@ module RedmineDmsf
           end
         elsif folder
           raise Forbidden unless User.current.admin? || User.current.allowed_to?(:folder_manipulation, project)
+          raise Forbidden unless DmsfFolder.permissions?(folder, false)
           folder.delete(false) ? NoContent : Conflict
         else
           MethodNotAllowed
@@ -271,11 +245,13 @@ module RedmineDmsf
         return PreconditionFailed if !resource.is_a?(DmsfResource) || resource.project.nil?
 
         parent = resource.parent
+        raise Forbidden unless (!parent.exist? || !parent.folder || DmsfFolder.permissions?(parent.folder, false))
 
         if collection?
           # At the moment we don't support cross project destinations
           return MethodNotImplemented unless (project.id == resource.project.id)
           raise Forbidden unless User.current.admin? || User.current.allowed_to?(:folder_manipulation, project)
+          raise Forbidden unless DmsfFolder.permissions?(folder, false)
 
           # Current object is a folder, so now we need to figure out information about Destination
           if dest.exist?
@@ -386,6 +362,7 @@ module RedmineDmsf
         return PreconditionFailed if !resource.is_a?(DmsfResource) || resource.project.nil?
 
         parent = resource.parent
+        raise Forbidden unless (!parent.exist? || !parent.folder || DmsfFolder.permissions?(parent.folder, false))
 
         if collection?
           # Current object is a folder, so now we need to figure out information about Destination
@@ -402,6 +379,7 @@ module RedmineDmsf
               User.current.allowed_to?(:view_dmsf_folders, resource.project) &&
               User.current.allowed_to?(:view_dmsf_files, project) &&
               User.current.allowed_to?(:view_dmsf_folders, project))
+          raise Forbidden unless DmsfFolder.permissions?(folder, false)
 
           return PreconditionFailed if (parent.projectless_path != '/' && !parent.folder)
           folder.title = resource.basename
@@ -552,6 +530,7 @@ module RedmineDmsf
       def put(request, response)
         raise BadRequest if collection?
         raise Forbidden unless User.current.admin? || User.current.allowed_to?(:file_manipulation, project)
+        raise Forbidden unless (!parent.exist? || !parent.folder || DmsfFolder.permissions?(parent.folder, false))
 
         # Ignore file name patterns given in the plugin settings
         pattern = Setting.plugin_redmine_dmsf['dmsf_webdav_ignore']
@@ -593,8 +572,7 @@ module RedmineDmsf
         else
           raise BadRequest unless (parent.projectless_path == '/' || (parent.exist? && parent.folder))
           f = DmsfFile.new
-          f.container_type = 'Project'
-          f.container_id = project.id
+          f.project_id = project.id
           f.name = basename
           f.dmsf_folder = parent.folder
           f.notification = !Setting.plugin_redmine_dmsf['dmsf_default_notifications'].blank?
@@ -677,6 +655,7 @@ module RedmineDmsf
       # also best-utilising DAV4Rack's implementation.
       def download
         raise NotFound unless (file && file.last_revision && file.last_revision.disk_file)
+        raise Forbidden unless (!parent.exist? || !parent.folder || DmsfFolder.permissions?(parent.folder))
 
         # If there is no range (start of ranged download, or direct download) then we log the
         # file access, so we can properly keep logged information
diff --git a/test/fixtures/dmsf_files.yml b/test/fixtures/dmsf_files.yml
index 2db9b629..2c3b6004 100644
--- a/test/fixtures/dmsf_files.yml
+++ b/test/fixtures/dmsf_files.yml
@@ -1,8 +1,7 @@
 ---
 dmsf_files_001:
   id:                 1
-  container_id:       1
-  container_type:     "Project"
+  project_id:         1
   dmsf_folder_id:     NULL
   name:               "test.txt"
   notification:       0
@@ -12,8 +11,7 @@ dmsf_files_001:
 #file on non-dmsf enabled project
 dmsf_files_002:
   id:                 2
-  container_id:       2
-  container_type:     "Project"
+  project_id:         2
   dmsf_folder_id:     NULL
   name:               "test.txt"
   notification:       0
@@ -23,8 +21,7 @@ dmsf_files_002:
 #deleted file on dmsf-enabled project
 dmsf_files_003:
   id:                 3
-  container_id:       1
-  container_type:     "Project"
+  project_id:         1
   dmsf_folder_id:     NULL
   name:               "deleted.txt"
   notification:       0
@@ -33,8 +30,7 @@ dmsf_files_003:
 
 dmsf_files_004:
   id:                 4
-  container_id:       1
-  container_type:     "Project"
+  project_id:         1
   dmsf_folder_id:     2
   name:               "test.txt"
   notification:       0
@@ -43,8 +39,7 @@ dmsf_files_004:
 
 dmsf_files_005:
   id:                 5
-  container_id:       1
-  container_type:     "Project"
+  project_id:         1
   dmsf_folder_id:     5
   name:               "test.txt"
   notification:       0
@@ -53,8 +48,7 @@ dmsf_files_005:
 
 dmsf_files_006:
   id:                 6
-  container_id:       1
-  container_type:     "Project"
+  project_id:         1
   dmsf_folder_id:     3
   name:               "test.txt"
   notification:       0
@@ -63,9 +57,8 @@ dmsf_files_006:
 
 dmsf_files_007:
   id:                 7
-  container_id:       1
-  container_type:     "Issue"
-  dmsf_folder_id:     NULL
+  project_id:         1
+  dmsf_folder_id:     8
   name:               "test.gif"
   notification:       0
   deleted:            0
@@ -73,8 +66,7 @@ dmsf_files_007:
 
 dmsf_files_008:
   id:                 8
-  container_id:       1
-  container_type:     "Issue"
+  project_id:         1
   dmsf_folder_id:     NULL
   name:               "test.pdf"
   notification:       0
@@ -83,8 +75,7 @@ dmsf_files_008:
   
 dmsf_files_009:
   id:                 9
-  container_id:       1
-  container_type:     "Project"
+  project_id:         1
   dmsf_folder_id:     NULL
   name:               "myfile.txt"
   notification:       0
@@ -93,8 +84,7 @@ dmsf_files_009:
   
 dmsf_files_010:
   id:                 10
-  container_id:       1
-  container_type:     "Project"
+  project_id:         1
   dmsf_folder_id:     NULL
   name:               "zero.txt"
   notification:       0
diff --git a/test/fixtures/dmsf_folders.yml b/test/fixtures/dmsf_folders.yml
index f4694543..1b681183 100644
--- a/test/fixtures/dmsf_folders.yml
+++ b/test/fixtures/dmsf_folders.yml
@@ -46,4 +46,12 @@ dmsf_folders_007:
   title:          folder7
   project_id:     1
   dmsf_folder_id: NULL
-  user_id:        1
\ No newline at end of file
+  user_id:        1
+
+dmsf_folders_008:
+  id:             8
+  title:          .Issues
+  project_id:     1
+  dmsf_folder_id: NULL
+  user_id:        1
+  system:         true
\ No newline at end of file
diff --git a/test/integration/rest_api/dmsf_file_api_test.rb b/test/integration/rest_api/dmsf_file_api_test.rb
index 96cd8596..d1c8d733 100644
--- a/test/integration/rest_api/dmsf_file_api_test.rb
+++ b/test/integration/rest_api/dmsf_file_api_test.rb
@@ -63,15 +63,13 @@ class DmsfFileApiTest < RedmineDmsf::Test::IntegrationTest
     # <dmsf_file>
     #   <id>1</id>
     #   <name>test.txt</name>
-    #   <container_id>1</container_id>
-    #   <container_type>Project</container_type>
+    #   <project_id>1</project_id>
     #   <version>1.0</version>
     #   <content_url>/dmsf/files/1/download</content_url>
     # </dmsf_file>
     assert_select 'dmsf_file > id', :text => @file1.id.to_s
     assert_select 'dmsf_file > name', :text => @file1.name
-    assert_select 'dmsf_file > container_id', :text => @file1.container_id.to_s
-    assert_select 'dmsf_file > container_type', :text => @file1.container_type.to_s
+    assert_select 'dmsf_file > project_id', :text => @file1.project_id.to_s
     assert_select 'dmsf_file > version', :text => "#{@file1.last_revision.major_version}.#{@file1.last_revision.minor_version}"
     assert_select 'dmsf_file > content_url', :text => "/dmsf/files/#{@file1.id}/download"
     #curl -v -H "Content-Type: application/octet-stream" -X GET -u ${1}:${2} http://localhost:3000/dmsf/files/41532/download > file.txt
diff --git a/test/integration/webdav/dmsf_webdav_propfind_test.rb b/test/integration/webdav/dmsf_webdav_propfind_test.rb
index 039a54a4..7dd48100 100644
--- a/test/integration/webdav/dmsf_webdav_propfind_test.rb
+++ b/test/integration/webdav/dmsf_webdav_propfind_test.rb
@@ -322,7 +322,7 @@ class DmsfWebdavPropfindTest < RedmineDmsf::Test::IntegrationTest
   def test_propfind_depth1_on_project1_for_admin_with_cache
     RedmineDmsf::Webdav::Cache.init_testcache
     
-    assert_difference 'RedmineDmsf::Webdav::Cache.cache.instance_variable_get(:@data).count', +8 do
+    assert_difference 'RedmineDmsf::Webdav::Cache.cache.instance_variable_get(:@data).count', +9 do
       xml_http_request :propfind, "/dmsf/webdav/#{@project1.identifier}", nil,
         @admin.merge!({:HTTP_DEPTH => '1'})
       assert_response 207 # MultiStatus
@@ -376,7 +376,7 @@ class DmsfWebdavPropfindTest < RedmineDmsf::Test::IntegrationTest
     log_user 'admin', 'admin' # login as admin
     assert !User.current.anonymous?, 'Current user is anonymous'
     
-    assert_difference 'RedmineDmsf::Webdav::Cache.cache.instance_variable_get(:@data).count', +8 do
+    assert_difference 'RedmineDmsf::Webdav::Cache.cache.instance_variable_get(:@data).count', +9 do
       xml_http_request :propfind, "/dmsf/webdav/#{@project1.identifier}", nil,
         @admin.merge!({:HTTP_DEPTH => '1'})
       assert_response 207 # MultiStatus
diff --git a/test/unit/dmsf_file_revision_test.rb b/test/unit/dmsf_file_revision_test.rb
index 2f734fc9..fcbd3ebe 100644
--- a/test/unit/dmsf_file_revision_test.rb
+++ b/test/unit/dmsf_file_revision_test.rb
@@ -60,9 +60,8 @@ class DmsfFileRevisionTest < RedmineDmsf::Test::UnitTest
   def test_new_storage_filename
     # Create a file.
     f = DmsfFile.new
-    f.container_type = 'Project'
-    f.container_id = 1
-    f.name = "Testfile.txt"
+    f.project_id = 1
+    f.name = 'Testfile.txt'
     f.dmsf_folder = nil
     f.notification = !Setting.plugin_redmine_dmsf['dmsf_default_notifications'].blank?
     f.save
@@ -74,7 +73,7 @@ class DmsfFileRevisionTest < RedmineDmsf::Test::UnitTest
     r1.dmsf_file = f
     r1.user = User.current
     r1.name = "Testfile.txt"
-    r1.title = DmsfFileRevision.filename_to_title("Testfile.txt")
+    r1.title = DmsfFileRevision.filename_to_title('Testfile.txt')
     r1.description = nil
     r1.comment = nil
     r1.mime_type = nil
diff --git a/test/unit/dmsf_file_test.rb b/test/unit/dmsf_file_test.rb
index ad872106..9aa1d8cc 100644
--- a/test/unit/dmsf_file_test.rb
+++ b/test/unit/dmsf_file_test.rb
@@ -208,18 +208,6 @@ class DmsfFileTest < RedmineDmsf::Test::UnitTest
     RedmineDmsf::Webdav::Cache.init_nullcache
   end
 
-  def test_container_project
-    container = @file1.container
-    assert_not_nil container
-    assert container.is_a?(Project)
-  end
-
-  def test_container_issue
-    container = @file7.container
-    assert_not_nil container
-    assert container.is_a?(Issue)
-  end
-
   def test_project_project
     project = @file1.project
     assert_not_nil project
diff --git a/test/unit/dmsf_folder_test.rb b/test/unit/dmsf_folder_test.rb
index b1e1b2e5..2dd826bc 100644
--- a/test/unit/dmsf_folder_test.rb
+++ b/test/unit/dmsf_folder_test.rb
@@ -53,7 +53,7 @@ class DmsfFolderTest < RedmineDmsf::Test::UnitTest
   def test_visiblity
     # The role has got permissions
     User.current = @manager
-    assert_equal 5, DmsfFolder.where(:project_id => 1).count
+    assert_equal 6, DmsfFolder.where(:project_id => 1).count
     assert_equal 5, DmsfFolder.visible.where(:project_id => 1).count
     # The user has got permissions
     User.current = @developer
@@ -65,10 +65,10 @@ class DmsfFolderTest < RedmineDmsf::Test::UnitTest
 
   def test_permissions
     User.current = @developer
-    assert DmsfFolder.permissions(@folder7)
+    assert DmsfFolder.permissions?(@folder7)
     @folder7.dmsf_folder_permissions.where(:object_type => 'User').delete_all
     @folder7.reload
-    assert !DmsfFolder.permissions(@folder7)
+    assert !DmsfFolder.permissions?(@folder7)
   end
 
   def test_delete
diff --git a/test/unit/project_patch_test.rb b/test/unit/project_patch_test.rb
index 91029865..e8bdc419 100644
--- a/test/unit/project_patch_test.rb
+++ b/test/unit/project_patch_test.rb
@@ -67,7 +67,7 @@ class ProjectPatchTest < RedmineDmsf::Test::UnitTest
 
   def test_dmsf_count
     hash = @project1.dmsf_count
-    assert_equal 7, hash[:files]
+    assert_equal 8, hash[:files]
     assert_equal 6, hash[:folders]
   end
 
@@ -79,7 +79,7 @@ class ProjectPatchTest < RedmineDmsf::Test::UnitTest
   end
 
   def test_copy_dmsf
-    assert_equal 3, @project1.dmsf_files.visible.count
+    assert_equal 4, @project1.dmsf_files.visible.count
     assert_equal 3, @project1.dmsf_folders.visible.count
     assert_equal 1, @project1.file_links.visible.count
     assert_equal 1, @project1.folder_links.visible.count
@@ -90,7 +90,7 @@ class ProjectPatchTest < RedmineDmsf::Test::UnitTest
     assert_equal 0, @project3.folder_links.visible.count
     assert_equal 0, @project3.url_links.visible.count
     @project3.copy_dmsf(@project1)
-    assert_equal 3, @project3.dmsf_files.visible.count
+    assert_equal 4, @project3.dmsf_files.visible.count
     assert_equal 3, @project3.dmsf_folders.count
     assert_equal 1, @project3.file_links.visible.count
     assert_equal 1, @project3.folder_links.visible.count