>>319 I did disable that annoying message when you open a downloaded app. It creates bugs apparently... I used terminal to enable it again, it's annoying, but it works now. And I guess it's safer :P
for anyone with the same problem, I entered this message in terminal :
defaults write com.apple.LaunchServices LSQuarantine -bool YES
("NO" would disable quarantine and create the bug)
press enter/return and restart your mac
PS: I'll give you my impressions on the beta later ;)