Bug 115711 [content assist] Parameter hints disappear immediately
org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/text/java/ParameterGuessingProposal.java
*/
	private String computeGuessingCompletion() throws JavaModelException {
		
		StringBuffer buffer= new StringBuffer(String.valueOf(fProposal.getName()));
		
		FormatterPrefs prefs= getFormatterPrefs();
		if (prefs.beforeOpeningParen)
			buffer.append(SPACE);
		buffer.append(LPAREN);
		
		if (prefs.afterOpeningParen)
			buffer.append(SPACE);
		
		fChoices= guessParameters();
		int count= fChoices.length;
		int replacementOffset= getReplacementOffset();
		
		for (int i= 0; i < count; i++) {
			if (i != 0) {
				if (prefs.beforeComma)
					buffer.append(SPACE);
				buffer.append(COMMA);
				if (prefs.afterComma)
					buffer.append(SPACE);
			}
			ICompletionProposal proposal= fChoices[i][0];
			String argument= proposal.getDisplayString();
			Position position= fPositions[i];
			position.setOffset(replacementOffset + buffer.length());
			position.setLength(argument.length());