(In reply to Daniel Holbert [:dholbert] from comment #4) > I'm not sure how much of a user-facing perf impact this would actually have, since no-op `width`/`height` animations should be relatively cheap Ah, Bramus [clarified on Twitter/X](https://x.com/bramus/status/1989071140204261840) that the main benefit here is keeping the whole animation looking smooth/responsive even in the presence of unrelated random jank from other stuff that's happening at the same time.
Bug 2000047 Comment 5 Edit History
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(In reply to Daniel Holbert [:dholbert] from comment #4) > I'm not sure how much of a user-facing perf impact this would actually have, since no-op `width`/`height` animations should be relatively cheap Ah, Bramus [clarified on Twitter/X](https://x.com/bramus/status/1989071140204261840) that the main benefit here isn't about reducing the cost of the animation, but rather to keep the animation looking smooth/responsive even in the presence of unrelated random jank from other stuff that's happening at the same time.