265566 - Fixed-pos kids are not clipped by CSS clip

Status: RESOLVED FIXED

(Core :: Web Painting, defect)

Description

[Boris Zbarsky [:bzbarsky]]

This is a problem in current builds.  The testcase at the URL is pretty
self-explanatory....

Comment 1

[Boris Zbarsky [:bzbarsky]]

Attachment: Testcase just in case Ian's server disappears somehow

Comment 2

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Attachment: fix

*sigh* I'm a bit sick of these clipping bugs. Perhaps this is the last one :-)

We were applying the 'clip' property to just the *geometric* descendants of the
element, but we should really be applying it to just the *content* descendants.
This patch does that. The patch also changes behaviour of
-moz-hidden-unscrollable the same way. That is arguably incorrect because
'overflow' normally affects just the *geometric* children. OTOH this is a
private property value, little used, and I don't want to add another code path
just for it. Let me know what you think.

Comment 3

[David Baron :dbaron: (⌚️UTC-4, no longer working on Mozilla)]

Comment on attachment 173129 [details] [diff] [review]
fix

r+sr=dbaron; sorry for the delay

Comment 4

[Robert O'Callahan (:roc) (email my personal email if necessary)]

Regression tested (no changes) and checked in.