Bug 61172 [rulers] quick assist hides quickfix icon
1) mistype a method call ->you get a quick fix but the quick fix is overlayed by the quick assist 2) press the quick assist icon ->you the the quick fix proposals
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/correction/QuickAssistLightBulbUpdater.java
if (elem instanceof ICompilationUnit) {
			return (ICompilationUnit) elem;
		}
		return null;
	}
	
	private IAnnotationModel getAnnotationModel() {
		return JavaUI.getDocumentProvider().getAnnotationModel(fEditor.getEditorInput());
	}
	
	private IDocument getDocument() {
		return JavaUI.getDocumentProvider().getDocument(fEditor.getEditorInput());
	}
	
	
	private void doSelectionChanged(int offset, int length, CompilationUnit astRoot) {
		
		final IAnnotationModel model= getAnnotationModel();
		final ICompilationUnit cu= getCompilationUnit();
		if (model == null || cu == null) {
			return;
		}
		
		final AssistContext context= new AssistContext(cu, offset, length);
		context.setASTRoot(astRoot);
		
		boolean hasQuickFix= hasQuickFixLightBulb(model, context.getSelectionOffset());
		if (hasQuickFix) {
			removeLightBulb(model);
			return;