Maybe I've just been lucky, but since I upgraded to Jaguar (currently 10.2.4), I haven't seen the "thumbnail scrambler" bug in iMovie 2. I've started to get used to being able to "undo" again, and that's been wonderful! Of course, just today I got hosed with the "automatically fade out" bug, so I had to go back and set all of my audio clips to "fade out" with a fade out duration of 0. Annoying. Maybe someday iMovie 3 will be usable, and I can finally switch. Hey, that might even make it worth my trouble to buy a new desktop Mac!