So this seems like and obvious thing, but It's got me beat, and I've scoured the internet for threads about this problem and I haven't found them. I'm doing a rough frame-by-frame animation and so I have a layer of the rough background, to be replaced by the finished background layer later. Then background is supposed to move in one sequence, so I go into edit mode with a keyframe of where it was and I drag it to where I want with a keyframe there in an appropriate place. Then I go to Interpolate-> interpolate and it says "Cannot find a pair of grease pencil frames to interpolate between in selected layer." Same result if I click interpolate->sequence. I know I'm not technically editing strokes, but surely there's some way to drag an object and tween it between points A and B? Thanks for your help all.