844178 - CSS position fixed no longer factors in scrollbar after hover

Status: RESOLVED FIXED

(Core :: Layout, defect)

Description

[peter.wm.wong]

Attachment: mozBugTestCase.html

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.8; rv:19.0) Gecko/20100101 Firefox/19.0
Build ID: 20130215130331

Steps to reproduce:

Setup:
 - Firefox 19.0
 - Mac OS X 10.8.2

1) Goto http://jsbin.com/ufatut/52
2) Notice the horizontal position of "HoverMe" text on the right (should be slight cut off of the "M")
3) Hover over the text
4) Notice the text moves to the RIGHT (not LEFT)
5) Un-hover the text
6) Notice the text does not move back to it's original position


Actual results:

Activating :hover psuedo class causes FF not to factor in the scrollbar anymore


Expected results:

The :hover psuedo class shouldn't cause the scrollbar to be ignored when positioning fixed positioned elements.

Comment 1

[peter.wm.wong]

A couple of sites we've noticed this affecting:
https://www.capitalone.com/
http://us.playstation.com/

On the right side, the "Feedback" Tab is affecting by this problem.

Comment 2

[Cork]

Last good nightly: 2012-06-06
First bad nightly: 2012-06-07

http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=6338a8988917&tochange=7e4c2abb9fc9

Comment 3

[Alice0775 White]

Regression window(m-c)
Good:
http://hg.mozilla.org/mozilla-central/rev/c29b842c4159
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:16.0) Gecko/16.0 Firefox/16.0a1 ID:20120606221720
Bad:
http://hg.mozilla.org/mozilla-central/rev/3933384d8315
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:16.0) Gecko/16.0 Firefox/16.0a1 ID:20120607023619
Pushlog:
http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=c29b842c4159&tochange=3933384d8315

Regression window(m-i)
Good:
http://hg.mozilla.org/integration/mozilla-inbound/rev/f5a441d6929f
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:16.0) Gecko/16.0 Firefox/16.0a1 ID:20120605210720
Bad:
http://hg.mozilla.org/integration/mozilla-inbound/rev/df6702c41ddd
Mozilla/5.0 (Windows NT 6.1; WOW64; rv:16.0) Gecko/16.0 Firefox/16.0a1 ID:20120605215419
Pushlog:
http://hg.mozilla.org/integration/mozilla-inbound/pushloghtml?fromchange=f5a441d6929f&tochange=df6702c41ddd

Triggered by:Bug 157681

Comment 4

[(no longer active)]

Jet, can you please find an owner for this?  I won't have the cycles to look into what's happening here... Thanks!

Comment 5

[peter.wm.wong]

Any idea when this will be fixed?

Comment 6

[Mats Palmgren (inactive)]

Attachment: Make RecomputePosition adjust the CB size as ViewportFrame::Reflow does.

Break out the special adjustments of the containing block rect that
ViewportFrame::Reflow does for reflowing its positioned children.
Use that from RecomputePosition().

https://tbpl.mozilla.org/?tree=Try&rev=a24861bb5e13

Comment 7

[Mats Palmgren (inactive)]

https://hg.mozilla.org/integration/mozilla-inbound/rev/a4fc2d70eade

Comment 8

[Timothy Nikkel (:tnikkel)]

We should probably get this on at least aurora.

Comment 9

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/a4fc2d70eade

Comment 10

[Lukas Blakk [:lsblakk] use ?needinfo]

This has been in product since FF!6, no need to track but please go ahead with an uplift nomination if this is deemed low risk.

Comment 11

[Ben Kol]

It seems that bug is related to the difference between "width" and "min-width": http://stackoverflow.com/a/15705522/980692