TextEditor painting jank

[anthony-nicholls]

This is the conversation I recall having with Jules (5 years and 16 days ago!).

CachedComponentImage invalidation logic

If the parent is buffered, then part of that image is the child component. So if the child needs repainting, of course the parent needs to invalidate its image! Having nested, buffered, opaque components that aren’t perfectly efficiently handled could just be an edge-case that was overlooked, or where it just wasn’t worth the extra step of checking for occlusion just to handle a rare situation.