I'm trying the latest VAX (1535). Sometimes when the suggestions list pops up none of the items is selected. Then I can't simply press Tab to auto-complete. Other times (for the same symbol) I'm getting the same suggestions list, but one of the items is selected.
This wasn't happening with the previous version I was using (1444, I think).
P.S. While I certainly agree that adding options for every little thing is generally a bad idea, VAX is the kind of tool that is aimed at improving productivity and every little bit of customization helps.