> I see that completion now works for user-defined variables, but:

> * completing with 'b' doesn't work at all

Right, that needs to be added for every shortcut.

> * completing with 'break' only completes the first directory that gets the TAB key
> * also, 'break' doesn't complete when I do another try to do auto-completion (works only on first try)

Indeed.  That should be fixed with this new version of the patch.