447626 - PrefBar extension makes Firefox 3.0 slow if ATI graphics card is used

Status: RESOLVED WORKSFORME

(Core :: XUL, defect)

Description

[Manuel Reimer]

Hello,

it would be nice if someone of the GFX team or someone who has good knowledge about the backend could help me with a problem, I'm unable to fix.

I got reported several times, that PrefBar 4.1.1 (http://prefbar.mozdev.org/) makes Firefox slower. For example scrolling in Bookmarks seems to get slower. "Tom" gave me an example on how to reproduce the bug on "public.mozdev.prefbar" (mozdev.org NNTP group):

| This is an example to make the GUI performance visible:
| - Select the File menu in Firefox 3
| - Hold down the Right Arrow key on the keyboard (Firefox menus being shuffled
|   through; observe speed)
| - Now uninstall Prefbar and repeat

So far I thought this only happens on Windows, but "Tom" uses Linux. All the persons that get this problem have ATI graphics cards. Noone with Nvida or other graphics cards ever reported this problem to me and also I am unable to reproduce it (only have Nvidia graphics cards in my computers). One windows user told me that reducing the "hardware accelleration" setting in the ATI driver one point below "maximum" solved the problem on his machine.

The problem doesn't exist on Firefox < 3.0.

What could cause this slowdown? Is this a bug in Core or am I able to fix this in PrefBar?

Some backgrounds aboug PrefBar:
- PrefBar adds a toolbar to the browser using an overlay.
- This toolbar is dynamically rendered using <template> and RDF
- Some modifications are done with Javascript. Some global Javascript resides in a global context, which is loaded onto the "hiddenDOMWindow".

Thanks in advance for any help. Please tell me if you need additional info.

Comment 1

[Ria Klaassen (not reading all bugmail)]

Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.1) Gecko/2008070208 Firefox/3.0.1

I tested this a few times on my laptop with ATI card and I see indeed some difference. 
I did a little competition: one profile with all my 22 extensions against another profile with only Prefbar and indeed, the one with only Prefbar was slower or at least, the highlights blinked irregularly like a Christmas tree.
 

Comment 2

[Ria Klaassen (not reading all bugmail)]

Well I found out that the issue with the horizontal scrolling through the menus was caused by Bug 279703. 

Comment 3

[Martijn Wargers (dead)]

I can reproduce this too, with the steps to reproduce. And I have a NVidia GeForce 7300 video card.
So this is not likely a GFX problem.

Comment 4

[Philip Chee]

Adding pref keyword. I don't think regression is appropriate here. Ria?

Comment 5

[:aceman]

Is this still a problem in Firefox 3.6 and prefbar 4.3.2?

And I do now understand comment 2:
Bug 279703 seems to be fixed in 2007, but the comment is from 2008. Is the bug still unfixed? Or was this bug caused by FIXING bug 279703?

This bug is set to BLOCK bug 279703. Shouldn't it DEPEND on it, if comment 2 is valid?

Comment 6

[Manuel Reimer]

I don't think that this bug still is relevant in any way. Closing.