Uninstall persona or enable menu bar. This is known bug in beta 1.

Flash problem. But 2 days ago Firefox 3.7 Alpha 2 was released with out-of-process plugins. Flash can no longer crash FF.

soo right... I use 3.6 NIGHTY. Every night it updates. 36 Extensions. My profile is 131MB big, 5 years old. Constantly ~20 tabs open. And i get crashes something like one time a month. All tabs recovered every time. And it uses half the memory of chrome.