575172 - Both the tablist and tabpreview icon is visible at the same time

Status: VERIFIED FIXED

(Core :: CSS Parsing and Computation, defect, P1)

Description

[Cork]

When browser.allTabs.previews is set to true. Untill the button is hovered both the preview icon and the tab list arrow is visible at the time.

Reproducible: Always

Steps to Reproduce:
1. Create a new profile
2. Go to about:config and set browser.allTabs.previews to true

Actual Results:  
The toolbar becomes slightly higher and both the for box icon and the arrow is shown.

Expected Results:  
The preview button should only have the four box icon.


This happens every time browser.allTabs.previews is set to true or firefox is restarted.

Regression range is http://hg.mozilla.org/mozilla-central/pushloghtml?fromchange=88fa0b783306&tochange=d4156799e66a

Comment 1

[Boris Zbarsky [:bzbarsky]]

This is likely relevant:

###!!! ASSERTION: Why did this not get handled while processing mRestyleRoots?: '!element->HasFlag(collector->tracker->RootBit()) || (element->GetFlattenedTreeParent() && (!element->GetFlattenedTreeParent()->GetPrimaryFrame()|| element->GetFlattenedTreeParent()->GetPrimaryFrame()->IsLeaf())) || (aData.mChangeHint & nsChangeHint_ReconstructFrame)', file ../../../mozilla/layout/base/RestyleTracker.cpp, line 120

Comment 2

[Boris Zbarsky [:bzbarsky]]

This is totally my fault.  Yay assertions (and even more yay code actually exercising this script type id stuff).

Comment 3

[Boris Zbarsky [:bzbarsky]]

Attachment: Proposed fix

Comment 4

[Boris Zbarsky [:bzbarsky]]

Cork, I should have mentioned this before but I really appreciate the clear and useful bug report!

Comment 5

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

http://hg.mozilla.org/mozilla-central/rev/05a7e8bafa8a

Comment 6

[Cork]

Verified in Mozilla/5.0 (X11; Linux x86_64; rv:2.0b6pre) Gecko/20100901 Firefox/4.0b6pre