If I don’t do Layer > Layer to Image Size before previewing, I get what the other commenter on this video posted (that is, random streaks of color and messed up preview results), and I’m using a version of GIMP more recent than what was available when the other poster made their post. The workaround I’ve been using every time I want to edit only a small part of a large layer is selecting, adjusting, cutting, and pasting, which nets me a floating selection that I can transform how I like accurately without affecting the preview of my animation with misaligned layers.
