Bug 6700 Code assist should not just beep
suggest to show a status message: Could not complete due to syntax errors. This is also better for accessability reasons.
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/javaeditor/CompilationUnitEditor.java
public void paintControl(PaintEvent event) {
				if (fTextWidget != null)
					handleDrawRequest(event.gc);
			}
			
			private void handleDrawRequest(GC gc) {
				
				if (fBracketPosition.isDeleted)
					return;
					
				int length= fBracketPosition.getLength();
				if (length < 1)
					return;
					
				int offset= fBracketPosition.getOffset();
				IRegion region= fSourceViewer.getVisibleRegion();
				
				if (region.getOffset() <= offset && region.getOffset() + region.getLength() >= offset + length) {
					offset -= region.getOffset();
					if (fMatcher.RIGHT == fAnchor)
						draw(gc, offset, 1);
					else 
						draw(gc, offset + length -1, 1);					
				}
			}
			
			private void draw(GC gc, int offset, int length) {
				if (gc != null) {
					Point left= fTextWidget.getLocationAtOffset(offset);