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
super(input.getFile());
				fInput= input;
				fCurrentEvent= new CompilationUnitAnnotationModelEvent(this, getResource());
			}
			
			protected MarkerAnnotation createMarkerAnnotation(IMarker marker) {
				return new JavaMarkerAnnotation(marker);
			}
			
			protected Position createPositionFromProblem(IProblem problem) {
				int start= problem.getSourceStart();
				if (start < 0)
					return null;
					
				int length= problem.getSourceEnd() - problem.getSourceStart() + 1;
				if (length < 0)
					return null;
					
				return new Position(start, length);
			}
			protected void update(IMarkerDelta[] markerDeltas) {
	
				super.update(markerDeltas);
				if (markerDeltas != null && markerDeltas.length > 0) {
					try {
						ICompilationUnit workingCopy = getWorkingCopy(fInput);
						if (workingCopy != null)
							workingCopy.reconcile(true, null);
					} catch (JavaModelException ex) {
						if (!ex.isDoesNotExist())