Gimp: toolbox display & main window resize issues in 12.10

I was having the same problem with GIMP and fixed it with the following steps:

1. Go to Edit > Preferences
2. Click on the Window Management option
3. Click "Reset Saved Window Positions to Default Values" button
4. Close GIMP

When you re-open GIMP, all of the toolboxes and window sizes should now be back to their defaults.

As for your Firefox problems, I can only suggest clearing out your cache and making sure you're running the latest version.