Yeah, I've tried everything-- changing the speed, the size, pausing and playing-- it doesn't change anything. Usually the preview window just shows that black & white background pattern, and occasionally flashes a couple frames of my image before going blank again.
It used to work perfectly. I think I started getting the problem after upgrading to a new version, but I've tried a few different versions since then and it didn't fix anything.
EDIT: HA! I think I fixed it
In preferences > View you can set the preview to high priority. Now it works the way it should.
