Bug 115711 [content assist] Parameter hints disappear immediately
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/java/ExperimentalProposal.java
LinkedModeUI ui= new EditorLinkedModeUI(model, getTextViewer());
				ui.setExitPosition(getTextViewer(), baseOffset + replacement.length(), 0, Integer.MAX_VALUE);
				ui.setExitPolicy(new ExitPolicy(')', document));
				ui.setDoContextInfo(true);
				ui.setCyclingMode(LinkedModeUI.CYCLE_WHEN_NO_PARENT);
				ui.enter();
				fSelectedRegion= ui.getSelectedRegion();
			} catch (BadLocationException e) {
				JavaPlugin.log(e);
				openErrorDialog(e);
			}
		} else {
			fSelectedRegion= new Region(baseOffset + replacement.length(), 0);
		}
	}
	
	/*
	 * @see org.eclipse.jdt.internal.ui.text.java.JavaMethodCompletionProposal#needsLinkedMode()
	 */
	protected boolean needsLinkedMode() {
		return false; 
	}
	
	/*
	 * @see org.eclipse.jdt.internal.ui.text.java.LazyJavaCompletionProposal#computeReplacementString()
	 */
	protected String computeReplacementString() {
		
		if (!hasParameters() || !hasArgumentList())
			return super.computeReplacementString();