Bug 17292 Inconsistent Undo behaviour for Cut/Copy/Paste in outline
Build 20020521 (freeze 1) 1) Open a java editor on some class 2) In the content outline, select a method and do Ctrl+X to cut 3) Notice in the menus, Edit->Undo and Refactor->Undo are disabled 4) Now select the type node in the content outline, and Ctrl+V to paste 5) Still, neither Undo action is enabled 6) Now click inside the editor area to give it focus. 7) Now "Edit->Undo" is possible. So, the problems are: 1) Undo is not consistent, it's available for Paste but not Cut. 2) Even when undo is possible, it only becomes enabled when the editor is activated.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/JavaOutlinePage.java
return null;
					
					IJavaElement element= delta.getElement();
					
					if (unit.equals(element))
						return delta;
					
					if (element.getElementType() > IJavaElement.CLASS_FILE)
						return null;
						
					IJavaElementDelta[] children= delta.getAffectedChildren();
					if (children == null || children.length == 0)
						return null;
						
					for (int i= 0; i < children.length; i++) {
						IJavaElementDelta d= findElement(unit, children[i]);
						if (d != null)
							return d;
					}
					
					return null;
				}
			};
			
			/**
			 * Content provider for the children of an ICompilationUnit or
			 * an IClassFile
			 * @see ITreeContentProvider
			 */
			class ChildrenProvider implements ITreeContentProvider {