I think that might be a different thing, Clark. My issue isn't not getting the completion list - I get it just fine. The problem is that it goes away again after 2 seconds. If I'm quick I can scroll down the list, pick the appropriate alias and have it insert the test as it should, so it is definitely there. It is just disappearing for no reason almost as soon as it pops up.
In my previous post I said it stays in place if I use Ctrl-. manually. I meant, of course, alt-.
However, I just unticked the FreeRTOS tag file but it made no difference.