diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/grid/AbstractBrowserGrid.java b/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/grid/AbstractBrowserGrid.java
index 6aa41c8c81ed21c7b937443ed48e8e7359081b7e..1df6d3e6c0a84ae205f46c0ee941bc800b17cf9a 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/grid/AbstractBrowserGrid.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/grid/AbstractBrowserGrid.java
@@ -1351,10 +1351,22 @@ public abstract class AbstractBrowserGrid<T/* Entity */, M extends BaseEntityMod
             if (data.isEmpty() == false)
             {
                 IBrowserGridActionInvoker invoker = asActionInvoker();
-                createDialog(data, invoker).show();
+                if (validateSelectedData(data))
+                {
+                    createDialog(data, invoker).show();
+                }
             }
         }
 
+        /**
+         * If specified data is valid returns true, otherwise returns false. Dialog will be shown
+         * only if this method returns true. Default implementation always returns true.
+         */
+        protected boolean validateSelectedData(List<T> data)
+        {
+            return true;
+        }
+
         protected abstract Dialog createDialog(List<T> data, IBrowserGridActionInvoker invoker);
     }
 
diff --git a/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/vocabulary/VocabularyGrid.java b/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/vocabulary/VocabularyGrid.java
index 732e03b4a913da7de14b424aa8300a3079f7fc39..56679e76d312c67a74f33c81e0f5260616ac3585 100644
--- a/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/vocabulary/VocabularyGrid.java
+++ b/openbis/source/java/ch/systemsx/cisd/openbis/generic/client/web/client/application/ui/vocabulary/VocabularyGrid.java
@@ -107,8 +107,8 @@ public class VocabularyGrid extends AbstractSimpleBrowserGrid<Vocabulary>
                             Vocabulary vocabulary = selectedItem.getBaseObject();
                             if (vocabulary.isManagedInternally())
                             {
-                                MessageBox.alert("Error",
-                                        "Internally managed vocabulary cannot be edited.", null);
+                                String errorMsg = "Internally managed vocabulary cannot be edited.";
+                                MessageBox.alert("Error", errorMsg, null);
                             } else
                             {
                                 createEditEntityDialog(vocabulary).show();
@@ -116,10 +116,11 @@ public class VocabularyGrid extends AbstractSimpleBrowserGrid<Vocabulary>
                         }
 
                     }));
-                    
+
         addButton(createSelectedItemsButton(viewContext.getMessage(Dict.BUTTON_DELETE),
                 new AbstractCreateDialogListener()
                     {
+
                         @Override
                         protected Dialog createDialog(List<Vocabulary> vocabularies,
                                 IBrowserGridActionInvoker invoker)
@@ -127,6 +128,21 @@ public class VocabularyGrid extends AbstractSimpleBrowserGrid<Vocabulary>
                             return new VocabularyListDeletionConfirmationDialog(viewContext,
                                     vocabularies, createDeletionCallback(invoker));
                         }
+
+                        @Override
+                        protected boolean validateSelectedData(List<Vocabulary> data)
+                        {
+                            String errorMsg = "Internally managed vocabulary cannot be deleted.";
+                            for (Vocabulary vocabulary : data)
+                            {
+                                if (vocabulary.isManagedInternally())
+                                {
+                                    MessageBox.alert("Error", errorMsg, null);
+                                    return false;
+                                }
+                            }
+                            return true;
+                        }
                     }));
         allowMultipleSelection(); // we allow deletion of multiple attachments