Since the latest update in Aurora from 6.0a2 to 7.0a2, the 'customize' context menu option on the toolbars will grey out when clicked, without actually popping up the customize panel, and the bookmarks toolbar becomes unusable. The bookmarks toolbar problem can be fixed by closing and reopening Aurora, however this bug seems to be persistent each time 'customize' is clicked.

I have not been able to find anywhere to notify bugs for the Aurora update channel so decided this was the best place to ask, searching for this on Google came out with no results, so assuming it may just be a problem on this install.