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
selectProposalWithMask(e.stateMask);
						break;
						
					
					
					case '\t':
							hide();
							break;
						
					default:			
						ICompletionProposal p= getSelectedProposal();
						if (p instanceof ICompletionProposalExtension) {
							ICompletionProposalExtension t= (ICompletionProposalExtension) p;
							char[] triggers= t.getTriggerCharacters();
							if (contains(triggers, key)) {
								hide();
								if (key == ';') {		
									e.doit= true;
									insertProposal(p, (char) 0, e.stateMask, fViewer.getSelectedRange().x);
								} else {
									e.doit= false;
									insertProposal(p, key, e.stateMask, fViewer.getSelectedRange().x);
								}
							}
						}
				}
			}
			
			return true;
		}