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
else
			fSelectionChangedListeners.remove(listener);
	}
	
	/*
	 * @see ISelectionProvider#setSelection(ISelection)
	 */
	public void setSelection(ISelection selection) {
		if (fOutlineViewer != null)
			fOutlineViewer.setSelection(selection);		
	}	
	
	/*
	 * @see ISelectionProvider#getSelection()
	 */
	public ISelection getSelection() {
		if (fOutlineViewer == null)
			return StructuredSelection.EMPTY;
		return fOutlineViewer.getSelection();
	}
	
	private void registerToolbarActions() {
		
		IToolBarManager toolBarManager= getSite().getActionBars().getToolBarManager();
		if (toolBarManager != null) {
			
			Action action= new LexicalSortingAction();
			toolBarManager.add(action);
			
			fMemberFilterActionGroup= new MemberFilterActionGroup(fOutlineViewer, "JavaOutlineViewer");