438955 - Navigation Toolbar Buttons UI borked when many multiple tabs are restored in new session

Status: VERIFIED INCOMPLETE

(Firefox :: General, defect)

Description

[Mark Edgar]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9) Gecko/2008052906 Firefox/3.0
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9) Gecko/2008052906 Firefox/3.0

When restarting a FF session when I have MANY (often >100) tabs opening, sometimes (~5-10% of the time) the navigation toolbar buttons are totally messed up on the right hand side, to the right of the search box, with a display of an extra 5 rows of twenty or so buttons on each row. These extra five rows of twenty buttons all appear to act as ONE huge button.

Closing Firefox and starting again eliminates the problem, with the session and UI displaying normally the next time, until it happens again, with no known trigger.

Reproducible: Sometimes

Steps to Reproduce:
1.Have MANY tabs open (I don't know the minimum number, but I'll often have >100 tabs open at a time, when it happens)
2.Close Firefox
3.Restart Firefox
Actual Results:  
5-10% of the time, the navigation toolbar UI is messed up, on the extreme right hand side, with a display of an extra HUGE button that is twenty icons wide by 5 rows deep, with ~85 icons displayed in it.

Expected Results:  
The navigation toolbar should display normally, without that extra button, with the ~85 icons on it there.

See screenshot at http://img443.imageshack.us/my.php?image=ffrc2whentaxedjw4.jpg for best way to understand what is going on. Note rectangle around icons on the right. That's because I had the cursor over the area, making it highlight like that, as if those icons are one big button.

Comment 1

[Mark Edgar]

Attachment: image of UI button problem

Comment 2

[Ria Klaassen (not reading all bugmail)]

This could be caused by an add-on. Can you also reproduce this in safe-mode?

Comment 3

[Simon Bünzli]

Closing as INCOMPLETE due to no feedback to comment #2 (otherwise it'd be WORKSFORME).