Hi! I'm new to Fresco so I may be doing something wrong but when I'm working on an image (could be image layer, pixel or vector or live brush, etc.) sometimes the screen flashes and everything I've done is suddenly pixelated and whited out. I can't undo the pixelation and am left to delete layers and start over. This is of course incredibly frustrating after putting time and effort into something. Any guidance would be much appreciated!