Bug 40785 [plan item] Overview ruler improvements
- navigation from ruler to editor - hovering over header area shows number of errors/warning (header annotations in general)
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitDocumentProvider.java
public void remove(Position position) {
				int index= getIndex(position);
				if (index > -1)
					fList.remove(index);
			}
			
			public void clear() {
				fList.clear();
			}
		}
		
		/**
		 * Annotation model dealing with java marker annotations and temporary problems.
		 * Also acts as problem requestor for its compilation unit. Initialiy inactive. Must explicitly be
		 * activated.
		 */
		protected class CompilationUnitAnnotationModel extends ResourceMarkerAnnotationModel implements IProblemRequestor, IProblemRequestorExtension {
			
			private IFileEditorInput fInput;
			private List fCollectedProblems;
			private List fGeneratedAnnotations;
			private IProgressMonitor fProgressMonitor;
			private boolean fIsActive= false;
			
			private ReverseMap fReverseMap= new ReverseMap();
			private List fPreviouslyOverlaid= null; 
			private List fCurrentlyOverlaid= new ArrayList();
			private CompilationUnitAnnotationModelEvent fCurrentEvent;
			public CompilationUnitAnnotationModel(IFileEditorInput input) {