1148581 - APZ ignores outer clip in this testcase

Status: RESOLVED FIXED

(Core :: Layout, defect)

Description

[Markus Stange [:mstange]]

Attachment: testcase

In this testcase, the red box should never leave the white box.

Comment 1

[Botond Ballo [:botond]]

Going to take this because I need it fixed to be able to test bug 1148582, and I want to make sure that my fix for bug 1145730 fixes bug 1148582 as well.

Comment 2

[Botond Ballo [:botond]]

This looks like a Layout issue - Layout is setting the clip for the container layer enclosing the red image layer differently with APZ enabled than with APZ disabled.

Comment 3

[Timothy Nikkel (:tnikkel)]

I bet we're failing to apply the clip of the outer overflow: hidden element because we clear the clipstate when we build the display list for the actually scrolling element, and then we add back in the clip for actively scrolling scroll frames that are parents of the scrolled content. Maybe we should save the current clip state on the scroll frame (so that we include overflow: hidden clips, but also CSS clip properties and any other clipping) and then apply that in ScrollFrameHelper::ComputeFrameMetrics.

Comment 4

[Timothy Nikkel (:tnikkel)]

The plan in bug 1148581 does comment 3 and more.

Comment 5

[Timothy Nikkel (:tnikkel)]

(In reply to Timothy Nikkel (:tn) from comment #4)
> The plan in bug 1148581 does comment 3 and more.

The plan in bug 1148582 does comment 3 and more.

Comment 6

[Botond Ballo [:botond]]

Updating dependencies to reflect the fact that the plan in bug 1148582 will fix this as well. Let's keep this open until bug 1148582 lands, and verify that the STR here is indeed fixed before closing.

Comment 7

[Markus Stange [:mstange]]

Fixed by bug 1148582.