I've just recently dicovered your product - and I absolutely adore it... so naturally when I learnt we could get a beta, I juumped at the chance.
So, I went and instlled the latest beta (v0.61 beta 2, I think...) everthing seemed fine then, poof, half of my extentions died - just like that!
In particular, I lost All-in-one Gestures (which was darn annoying), ShowIP (which wasn't quite so bad) and Minimizetotray (also really annoying.) I may have also lost other, less loved extensions, but I haven't really tested it all fully.
Distressed, I uninstalled the beta, and they came back to life. Then I re-installed v0.60 and it was still all OK.
Now, I'm no techie, but I think there might be a conflict with these or other extensions.
Heres a full list of the extensions I have installed:
Adblock - v.5 d2 * nightly 39
Disable Targets For Downloads - v0.9
Forecastfox - v0.7.9.2
Tabbrowser Preferences - v1.2.7.1
PDF Download - v0.4.1.3
All-in-One Gestures - v0.15.2
Bandwidth Tester - v0.54
Minimize to Tray - v0.0.1.2005061123+
Customize Google - v0.19.5
SecurePassword Generator - v0.5.2 (redundant now I've found your extension! :D)
ShowIP - v0.7.8
Add N Edit Cookies - v0.2.0.4
PasswordMaker - v0.6/v0.61 beta2