Sometimes the preview is frozen in the sense that I can't click on links between images when the CP Editor is open, or I cant bring up individual images when in Layers Mode. To get it working properly, I have to move the mouse over the Layers panel. Yes, just move it over that panel, I don't have to click anything, and then I can click on links etc. This is not new to RC1, it's been that way for a while.

Gentoo Linux, nvidia drivers 30*.* (currently on 304.64).