This doesn't happen with a fresh profile, but as many users will be upgrading from the older version or RC2 i think we need to fix this. It was introduced with the Colors tab appearance in the preferences. This happens on my system which i'm upgrading from earlier SVN versions to the recent (on top). For me (on XP) it opens fine, but left panel gets squeezed when i go to Colors tab. On Win7 x64 it gets squeezed when you just open the Preferences.