beta 2.0.4.2007.06.26: MacOSx crash/freeze resolved
An issue was noticed where-in Firefox froze or crashed when the preferences/options window was opened. This only happens when browser.preferences.animatefadein is set to true (which is the default on Mac). This happened because of some fade-in issues when the preferences box contains scripts which refer to elements outside the prefpane. refer XUL_FAQ#Troubleshooting_prefwindow-based_options_windows (the second last point.)
The issue (I believe) has been fixed but will only be confirmed and released in the new version if you provide feedback confirming the resolution.
Cheers!