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
ICompletionProposal proposal= getSelectedProposal();
			if (proposal instanceof ICompletionProposalExtension2) {
				ICompletionProposalExtension2 extension= (ICompletionProposalExtension2) proposal;
				extension.unselected(fViewer);
			}
		}
		if (Helper2.okToUse(fProposalShell)) {
			fContentAssistant.removeContentAssistListener(this, ContentAssistant2.PROPOSAL_SELECTOR);
			
			fPopupCloser.uninstall();
			fProposalShell.setVisible(false);
			fProposalShell.dispose();
			fProposalShell= null;
		}
		
		if (fAdditionalInfoController != null) {
			fAdditionalInfoController.dispose();
		}
		
		fFilteredProposals= null;
		
		fContentAssistant.possibleCompletionsClosed();
	}
	
	/**
	 *Returns whether this popup is active. It is active if the propsal selector is visible.
	 *
	 * @return <code>true</code> if this popup is active
	 */
	public boolean isActive() {