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
/**
	 * Selects the entry with the given index in the proposal selector and feeds
	 * the selection to the additional info controller.
	 * 
	 * @param index the index in the list
	 * @param smartToggle <code>true</code> if the smart toogle key has been pressed
	 * @since 2.1
	 */
	private void selectProposal(int index, boolean smartToggle) {
		ICompletionProposal oldProposal= getSelectedProposal();
		if (oldProposal instanceof ICompletionProposalExtension2)
			((ICompletionProposalExtension2) oldProposal).unselected(fViewer);
		ICompletionProposal proposal= fFilteredProposals[index];
		if (proposal instanceof ICompletionProposalExtension2)
			((ICompletionProposalExtension2) proposal).selected(fViewer, smartToggle);
	
		
		fProposalTable.setSelection(index);
		fProposalTable.showSelection();
		if (fAdditionalInfoController != null)
			fAdditionalInfoController.handleTableSelectionChanged();
	}
	
	/**
	 * Returns whether the given character is contained in the given array of 
	 * characters.
	 * 
	 * @param characters the list of characters
	 * @param c the character to look for in the list