It took me a while to isolate where the problem comes up but I've narrowed it down to this:
If I have an html tag in my jsp like so: ">
The content assist won't work for the jsp expression Defs.NAME if it's inside an html tag (ie between <>)
If I do this: <%=Defs.NAME%> then the content assist works fine. It just has to be outside the html brackets.
When I say it doesn't work, I mean the box comes up with no suggestions. Whereas 'works fine' means it gets all the suggestions in scope.
Worked fine in ganymede.
Turns out this is a bug in helios that's fixed in sr2.