Markus Stange [:mstange] Reporter
	Description • 9 years ago

After lifting two fingers from the touchpad, overlay scrollbars should fade away with an animation. This animation was broken recently.

43:38.78 LOG: MainThread Bisector INFO Pushlog:
https://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=5b59f670cf52f7c4bb5f2fde2c4174d64f7a1f7e&tochange=7d3ce51b85e3a9e79582d947bfdf3708c322328b

 -> bug 1157984

	Markus Stange [:mstange] Reporter
	Comment 1 • 9 years ago

[Tracking Requested - why for this release]: regression

	Milan Sreckovic [:milan] (needinfo for best results)
	Comment 2 • 9 years ago

Is this with APZ only?

	Markus Stange [:mstange] Reporter
	Comment 3 • 9 years ago

Looks like it is, yes!

	:kip (Kearwood Gilbert) Assignee
	Comment 4 • 9 years ago

I have narrowed this regression down to the change in CompositorOGL.cpp in the "Part 3" patch applied in Bug 1157984:

+  Rect destRect = aTransform.TransformAndClipBounds(aRect, aClipRect);
-  Rect destRect = aTransform.TransformBounds(aRect);

Perhaps this is causing the layer that renders the scrollbar overlay to be culled out during the fading sequence.

Possibly, aClipRect needs an offset applied similar to how it is used later in the same function.  An maximum sized rectangle for the coordinate system may be equally effective here.

I'll continue to investigate.

	:kip (Kearwood Gilbert) Assignee
	Comment 5 • 9 years ago

I have created a patch for Bug 1207326, which corrects this bug also.

	:kip (Kearwood Gilbert) Assignee
	Comment 6 • 9 years ago

Once Bug 1207326 lands, this should be fixed.  Shall we mark as duplicate?

	u279076
	Comment 7 • 9 years ago

Markus, can you confirm if this is resolved now?

	Markus Stange [:mstange] Reporter
	Comment 8 • 9 years ago

Yes, this is fixed in today's nightly.