So this is essentially the same thing discussed in bug 1764655 comment 9: > Anything that causes reconstruct of the frame of a oop iframe could lead to this flicker. In that bug (bug 1764655), it was dynamic `scrollbar-width` changes, and we were able to land a patch to avoid reconstructing frames for that case. In this bug, it's `overflow` changes (between `visible` and non-`visible`), where I suspect we can't avoid reconstructing frames, since the frame type is different, since it toggles between requiring/not-requiring a `ScrollContainerFrame` wrapper for the element. So: - frame-reconstruction here is probably unavoidable. - But I think the flicker itself might be avoidable... Probably bug 1750189 would help with this, if I'm reading it (and bug 1764655 comment 7) correctly.
Bug 1910887 Comment 7 Edit History
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So this is essentially the same thing discussed in bug 1764655 comment 9: > Anything that causes reconstruct of the frame of a oop iframe could lead to this flicker. In that bug (bug 1764655), it was dynamic `scrollbar-width` changes, and we were able to land a patch to avoid reconstructing frames for that case. In this bug, it's `overflow` changes (between `visible` and non-`visible`), where I suspect we can't avoid reconstructing frames, since the container's frame type is necessarily changing with the dynamic restyle -- it toggles between requiring/not-requiring a `ScrollContainerFrame` wrapper for the element. So: - frame-reconstruction here is probably unavoidable. - But I think the flicker itself might be avoidable... Probably bug 1750189 would help with this, if I'm reading it (and bug 1764655 comment 7) correctly.