Bug 19014 Empty CU after reorg
F2 - enable single click and show in members in packages view - open TestCase.java in editor - give focus to packages view - change it on disk - copy a method in TestCase using DnD - activate the TestCase.java editor - answer question with no - activate revert from context menu observe: CU is empty
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitDocumentProvider.java
if (temporaryProblemsChanged)
					fireModelChanged(new CompilationUnitAnnotationModelEvent(this, getResource(), false));
			}
			
			private void removeMarkerOverlays(boolean isCanceled) {
				if (isCanceled) {
					fCurrentlyShadowed.addAll(fPreviouslyShadowed);
				} else {
					Iterator e= fPreviouslyShadowed.iterator();
					while (e.hasNext()) {
						JavaMarkerAnnotation annotation= (JavaMarkerAnnotation) e.next();
						annotation.setOverlay(null);
					}
				}			
			}
			
			private void setOverlay(Object value, ProblemAnnotation problemAnnotation) {
				if (value instanceof  JavaMarkerAnnotation) {
					JavaMarkerAnnotation annotation= (JavaMarkerAnnotation) value;
					if (annotation.isProblem()) {
						annotation.setOverlay(problemAnnotation);
						fPreviouslyShadowed.remove(annotation);
						fCurrentlyShadowed.add(annotation);
					}
				}
			}
			
			private void  overlayMarkers(Position position, ProblemAnnotation problemAnnotation) {
				Object value= getAnnotations(position);
				if (value instanceof List) {