1011639 - Sub-APZC busted when preceded by a non scrolling div

Status: RESOLVED FIXED

(Core :: Panning and Zooming, defect)

Description

[Benoit Girard (:BenWa)]

Testcase:
http://people.mozilla.org/~bgirard/scroll.html

This should be getting APZC but instead only appears to scroll from main thread transactions.

Comment 1

[Benoit Girard (:BenWa)]

Attachment: Layer tree

Comment 2

[Kartikaya Gupta (email:[e-mail])]

Attachment: ScrollLayer merging fail

The display list dump shows that we are unable to merge the scroll layers so we end up with a scrollinfo layer instead.

Comment 3

[Timothy Nikkel (:tnikkel)]

The page has one stacking context, the text on the page goes into the content layer, the background goes into the background layer, so when the layers get flattened the text above the scrollable div is above the background of the scrolling div. This is the same as bug 939239/bug 933264. The proper solution to this is bug 967844. If it's an important use case that we can't improve ourselves we could possibly try to hack around it.

Given that unassigning, re-assign if we need quicker action then bug 967844 for this.

Comment 4

[Kartikaya Gupta (email:[e-mail])]

Attachment: Test case from comment 0

Saving the test case on the bug in case benwa decides to change it or remove it.

Comment 5

[Milan Sreckovic [:milan] (needinfo for best results)]

Is there any more work left on this with bug 967844 landed, or can we close it?

Comment 6

[Kartikaya Gupta (email:[e-mail])]

I was going to wait until bug 1063158 was fixed so that we could verify this bug using the visual indicator (bug 1053992). Technically this one is fixed, though, so we could close if we wanted to.

Comment 7

[Kartikaya Gupta (email:[e-mail])]

Confirmed fixed by bug 967844.