Bug 115711 [content assist] Parameter hints disappear immediately
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/java/ParameterGuessingProposal.java
super(proposal, context.getContext(), cu, labelProvider);
		fInvocationContext= context;
 	}
	/*
	 * @see ICompletionProposalExtension#apply(IDocument, char)
	 */
	public void apply(IDocument document, char trigger, int offset) {
		try {
			super.apply(document, trigger, offset);
			
			int baseOffset= getReplacementOffset();
			String replacement= getReplacementString();
			
			if (fPositions != null && getTextViewer() != null) {
				
				LinkedModeModel model= new LinkedModeModel();
				
				for (int i= 0; i < fPositions.length; i++) {
					LinkedPositionGroup group= new LinkedPositionGroup();
					int positionOffset= fPositions[i].getOffset();
					int positionLength= fPositions[i].getLength();
				
					if (fChoices[i].length < 2) {
						group.addPosition(new LinkedPosition(document, positionOffset, positionLength, LinkedPositionGroup.NO_STOP));
					} else {
						ensurePositionCategoryInstalled(document, model);
						document.addPosition(getCategory(), fPositions[i]);
						group.addPosition(new ProposalPosition(document, positionOffset, positionLength, LinkedPositionGroup.NO_STOP, fChoices[i]));
					}
					model.addGroup(group);