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
if (window == null)
			return null;
		return getWorkbench().getActiveWorkbenchWindow().getActivePage();
	}
		
	public synchronized CompilationUnitDocumentProvider getCompilationUnitDocumentProvider() {
		if (fCompilationUnitDocumentProvider == null)
			fCompilationUnitDocumentProvider= new CompilationUnitDocumentProvider();
		return fCompilationUnitDocumentProvider;
	}
	
	public synchronized ClassFileDocumentProvider getClassFileDocumentProvider() {
		if (fClassFileDocumentProvider == null)
			fClassFileDocumentProvider= new ClassFileDocumentProvider();
		return fClassFileDocumentProvider;
	}
	public synchronized IWorkingCopyManager getWorkingCopyManager() {
		return getCompilationUnitDocumentProvider();
	}
	
	public synchronized ProblemMarkerManager getProblemMarkerManager() {
		if (fProblemMarkerManager == null)
			fProblemMarkerManager= new ProblemMarkerManager();
		return fProblemMarkerManager;
	}	
	
	public synchronized JavaTextTools getJavaTextTools() {
		if (fJavaTextTools == null)
			fJavaTextTools= new JavaTextTools(getPreferenceStore());
		return fJavaTextTools;