Looking at the JavaDoc of [IQuickAssistProcessor](http://publib.boulder.ibm.com/infocenter/iadthelp/v6r0/index.jsp?topic=/org.eclipse.jdt.doc.isv/reference/api/org/eclipse/jdt/ui/text/java/IQuickAssistProcessor.html), it should return ``null`` when no proposals can be offered. Not sure if it makes any difference though.