I am a pro user but I have never seen something like this. When I'm trying to select several frames on 4 layers, the selection dissapear! I can't finish my work, I didn't change any preferences, nothing :[ I changed mouse - the same. There is no info in the Internet about this error Did u meet that bug before? Please help me. Cheers.
If you are trying click and drag to select multiple frames in multiple layers and that won't work, try clicking on the first frame that you want and then hold the shift key and click on the last frame. Do either of those work? Both should. If not, you may need yet another mouse.