Bug 42587 Left over from content assist
M3 - set preference that content assist should overwrite - open content assist on some word so that the rest of the word is indicated to be overwritten - transfer focus to the content assist widget using TAB - Esc -> overwrite indication is still there
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/link/contentassist/CompletionProposalPopup2.java
* 
	 * @param p the completion proposal
	 * @param trigger the trigger character
	 * @param offset the offset
	 * @since 2.1
	 */
	private void insertProposal(ICompletionProposal p, char trigger, int stateMask, int offset) {
			
		fInserting= true;
		IRewriteTarget target= null;
		
		try {
			
			IDocument document= fViewer.getDocument();
			
			if (fViewer instanceof ITextViewerExtension) {
				ITextViewerExtension extension= (ITextViewerExtension) fViewer;
				target= extension.getRewriteTarget();
			}
			
			if (target != null)
				target.beginCompoundChange();
			
			if (p instanceof ICompletionProposalExtension2) {
				ICompletionProposalExtension2 e= (ICompletionProposalExtension2) p;
				e.apply(fViewer, trigger, stateMask, offset);				
			} else if (p instanceof ICompletionProposalExtension) {
				ICompletionProposalExtension e= (ICompletionProposalExtension) p;
				e.apply(document, trigger, offset);
			} else {