999643 - Missing transitions on children of containers with overflow:[auto|scroll] and :before pseudo element

Status: RESOLVED FIXED

(Core :: Layout, defect)

Description

[munter]

When a parent element has the css properties overflow: hidden|auto; in either dimension and both :before and :after, transitions on child elements do not animate, but are skipping directly to the end.

Confirmed in Firefox 19, 26, 27, 28 on Windows 7, OSX Maverick and Linux

Comment 1

[munter]

See http://codepen.io/Munter/pen/GKHek for example

Possibly related: https://bugzilla.mozilla.org/show_bug.cgi?id=913588

Comment 2

[Daniel Holbert [:dholbert]]

Attachment: reduced testcase 1

This seems to happen specifically for :before, and specifically when the style change is triggered via a descendant selector, with :hover on the ancestor.

I'm using "body:hover i" in this testcase. "div:hover i" has the same broken results (as shown in the codepen).

Notably, though, if I tweak the testcase to replace "body:hover i" with "body i:hover" (or just "i:hover"), then I get smooth transitions in all cases.

Comment 3

[Daniel Holbert [:dholbert]]

And yes, this does look related to bug 913588. Setting dependency (though it may end up being a duplicate).

Comment 4

[Boris Zbarsky [:bzbarsky]]

Chances are, the patch in bug 990340 fixes this.

Comment 5

[Mats Palmgren (inactive)]

Should be fixed in Nightly in a few days, by bug 990340.

Comment 6

[munter]

Thanks for the quick handling :)