I recently installed 12.10. When Gimp is launched, its main window extends below the bottom of the screen, and cannot be resized vertically, only horizontally. Also, the toolbox window isn't displayed correctly; it doesn't have a title, nor is it framed. Instead, all the toolbox icons appear in a single column that extends below the bottom of the screen. The problem persists after reinstalling Gimp.

In case it's relevant, I'm having two other graphics-related issues: text in Firefox frequently gets garbled, and the whole system periodically freezes, either for a few seconds or without returning to normal. I'm running Intel integrated graphics (controller i915).