Bug 28244 Edit->Undo / Refactor->Undo don't play well together
reproducible in I20021210 with the following steps and code: - select "b + c" - extract local - edit->undo - refactor->undo public class Test { public Test() { int a= 1; int b= 2; int c= 3; int d= a + b + c; } }
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/JavaPlugin.java
* The id of the problem hover contributed for extension point
	 * <code>javaEditorTextHovers</code>.
	 *
	 * @since 2.1
	 */
	public static String ID_PROBLEM_HOVER= "org.eclipse.jdt.ui.ProblemHover"; 
		
	private static JavaPlugin fgJavaPlugin;
	private CompilationUnitDocumentProvider fCompilationUnitDocumentProvider;
	private ClassFileDocumentProvider fClassFileDocumentProvider;
	private JavaTextTools fJavaTextTools;
	private ProblemMarkerManager fProblemMarkerManager;
	private ImageDescriptorRegistry fImageDescriptorRegistry;
	
	private JavaElementAdapterFactory fJavaElementAdapterFactory;
	private MarkerAdapterFactory fMarkerAdapterFactory;
	private EditorInputAdapterFactory fEditorInputAdapterFactory;
	private ResourceAdapterFactory fResourceAdapterFactory;
	private MembersOrderPreferenceCache fMembersOrderPreferenceCache;
	
	
	public static JavaPlugin getDefault() {
		return fgJavaPlugin;
	}
	
	public static IWorkspace getWorkspace() {
		return ResourcesPlugin.getWorkspace();
	}
	
	public static IWorkbenchPage getActivePage() {