While checking Greg's patch on bug 1130016 I noticed that even though his code removed the touchstart listener, the force-dtc flag still persisted on the layer. This happens because the layer at [1] is reused across paints, and we only set the override flag but we never clear it. This is an error in the refactoring patch I landed for bug 1131840. [1] http://mxr.mozilla.org/mozilla-central/source/layout/base/nsDisplayList.cpp?rev=96d7198bec0a#4171

Comment on attachment 8569318 [details] [diff] [review] Patch Review of attachment 8569318 [details] [diff] [review]: ----------------------------------------------------------------- Tricky!

Comment on attachment 8569318 [details] [diff] [review] Patch NOTE: Please see https://wiki.mozilla.org/Release_Management/B2G_Landing to better understand the B2G approval process and landings. [Approval Request Comment] Bug caused by (feature/regressing bug #): regression from bug 1131840 User impact if declined: in some cases the APZ will perform less well than it should, because we weren't properly tracking removal of touch listeners from the DOM. Honestly the impact of this is low unless we also land bug 1116579 but the risk is also quite low so requesting uplift anyway. Testing completed: locally Risk to taking this patch (and alternatives if risky): very low risk, just fixes a refactoring error. String or UUID changes made by this patch: none