diff --git a/app/models/dmsf_query.rb b/app/models/dmsf_query.rb
index d6742560..20e8deba 100644
--- a/app/models/dmsf_query.rb
+++ b/app/models/dmsf_query.rb
@@ -146,7 +146,7 @@ class DmsfQuery < Query
             "SELECT ct.id FROM dmsf_folders ct LEFT OUTER JOIN custom_values ON custom_values.customized_type='DmsfFolder' AND custom_values.customized_id=ct.id AND custom_values.custom_field_id=",
             'SELECT custom_values.customized_id FROM custom_values WHERE custom_values.customized_type=dmsf_folders.customized_type AND custom_values.customized_id=dmsf_folders.customized_id AND custom_values.custom_field_id=')
           sql_cf.gsub! 'WHERE dmsf_folders.id = ct.id AND   (', 'AND '
-          sql_cf.gsub!(/\)$/, '')
+          sql_cf.gsub! /\)$/, ''
           filters_clauses << sql_cf
         else
           filters_clauses << '(' + sql_for_field(field, operator, v, queried_table_name, field) + ')'
diff --git a/test/functional/dmsf_controller_test.rb b/test/functional/dmsf_controller_test.rb
index bef12411..50d00994 100644
--- a/test/functional/dmsf_controller_test.rb
+++ b/test/functional/dmsf_controller_test.rb
@@ -235,6 +235,16 @@ class DmsfControllerTest < RedmineDmsf::Test::TestCase
     assert_select 'a', text: @file10.title, count: 0
   end
 
+  def test_show_filters_custom_field
+    get :show, params: { id: @project1.id, set_filter: '1', f: ['cf_21', ''], op: { 'cf_21' => '=' },
+                         v: { 'cf_21' => ['User documentation']} }
+    assert_response :success
+    # Folder 1 with Tag=User documentation
+    assert_select 'a', text: @folder1.title
+    # Other document/folders are not present
+    assert_select 'a', text: @file10.title, count: 0
+  end
+
   def test_show_without_file_manipulation
     @role_manager.remove_permission! :file_manipulation
     get :show, params: { id: @project1.id }