537392 - Linux Firefox - flicker when reloading/switching webpages containing DIVs with overflow:auto

Status: UNCONFIRMED

(Core :: Layout, defect)

Description

[Ralph Moenchmeyer]

User-Agent:       Mozilla/5.0 (X11; U; Linux x86_64; de; rv:1.9.1.6) Gecko/20091201 SUSE/3.5.6-5.1 Firefox/3.5.6
Build Identifier: Mozilla/5.0 (X11; U; Linux x86_64; de; rv:1.9.1.6) Gecko/20091201 SUSE/3.5.6-5.1 Firefox/3.5.6

Some of the web pages which I develop for content management purposes contain DIVs with the CSS directive 
overflow:auto; 

Recently, I noticed a strange, statistical but frequent flicker effect for such pages in my Linux Firefox (version 3.5.6 on KDE 4.3.4, Opensuse 11.2, x86_64 with quadcore proc.):  

Whilst reloading pages (containing DIVs with overflow-options) or switching between such pages, the contents of the DIV (with the overflow setting) is first displayed at a wrong and shifted position for a tiny part of a second. Afterwards, it appears at the defined position. 

During a reload of the page the original page is displayed whilst the DIV content flickers/appears shortly at a wrong position. I.e., for a blink of an eye the DIV contents appears twice - at the orginal correct position and at a shifted position.  

It seems that a kind of re-rendering of the page starts while the position of the DIV content is still being calculated. Deleting the overflow directive removes the flicker effect completely.      

This only happens in Firefox on Linux with KDE 4 (oxygen active). It does not occur in Firefox for Windows XP. It does not occur in Opera (neither Linux nor Windows version), nor in KDE's Konqueror. 



  

Reproducible: Always

Steps to Reproduce:
1. Go to the URL above.
2. Click fast and several times on the reload button of your Linux 3.5.6 FF browser  
3. Watch the flicker effect and the shifted display of the yellowish box during the flicker 
Actual Results:  
Flicker - statistical, but rather frequent and reproducible

Expected Results:  
static display - no flicker 

(as it is the case with Konqueror and Opera or FF for Windows)

The test page at the URL above is a reduced version derived from a more complex PHP ITX template. Please, do not worry about the strange {} place holders. The flicker does also occur when all placeholders are filled with reasonable values from PHP applications.   

If one removes the "overflow:auto" and "overflow-x:hidden" directives in the CSS file named "pfl_single.css" for the div with id="div_out_pfl" no flicker occurs any longer.

Comment 1

[David Dahl :ddahl]

Cannot reproduce using Gnome either using Namoroka: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2b6pre) Gecko/20091231 Namoroka/3.6b6pre

Comment 2

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

We stopped using native (GTK) widgets for scrollable regions in 1.9.2 / Firefox 3.6, so I'd expect this to be fixed.

Comment 3

[Ralph Moenchmeyer]

Yes, GTK widgets are used in my Firefox version 3.5.    
OK, I'll wait for the RPMs of the 3.6 version for Opensuse and give you a feedback then.

Comment 4

[David Baron :dbaron: (⌚️UTC-5, no longer working on Mozilla)]

This is probably a duplicate of one of the bugs listed in the "Blocks" section of https://bugzilla.mozilla.org/showdependencytree.cgi?id=352093&maxdepth=1&hide_resolved=0

Comment 5

[Ralph Moenchmeyer]

Meanwhile I tried to reproduce the flicker on another system. Major differences to my system: KDE is of the older version 4.3.1, the Opensuse version is 11.1. The other system has a Nvidia card, too, but a different one than the graphics card  installed on my system. However, the same Nvidia driver is used on both systems. 

Otherwise the systems are quite comparable (same quad core CPU, same motherboard, etc.). 

Test result: No flicker on the KDE 4.3.1 system !

Could the reason be be a Suse 11.2 problem ? Or a problem of KDE 4.3.4 ? Or some changes in the qt or gtk libraries ? 

I intend to upgrade the Opensuse11.1/KDE 4.31. system soon to Opensuse 11.2/KDE 4.3.4. I'll give a new feedback, then.

Comment 6

[Ralph Moenchmeyer]

An hour ago I performed a fresh installation of Opensuse 11.2 on the other system I discussed in my last comment (5). I.e. on the system which (originally) had Opensuse 11.1 and KDE 4.3.1 on it and showed no FF flicker effect for this (old) configuration. Actually I still have the old configuration available on a different partition for further comparisons and tests. 

Now with Opensuse 11.2, KDE 4.3.1 (!) from SUSE I opened my testpage with Firefox 3.5.6 (the latter also installed from SUSE). (No proprietory nvidia driver installed.) Guess what happened: The flicker effect appeared at once when I pressed the reload button several times ! 

Conclusion: 
The problem is not due to Nvidia drivers or differences in the graphics card. It does not appear under Opensuse 11.1 with KDE 4.3.1. However, it appears under Opensuse 11.2 even for KDE 4.3.1. So the problem does not depend on a specific KDE 4.3.x version. 

Furthermore I tested whether the flicker appears under Gnome. The answer is YES for Opensuse 11.2 on both of my systems. So, it is no specific KDE effect. 

Any ideas what to check next ? Any specific information you would need to clarify the problem ? 

By the way: I checked other pages which contain DIVs with overflow:auto. In all cases there are flickery effects due to wrong positions of some elements within the DIV for maybe 0.2 - 0.3 seconds.

Comment 7

[Ralph Moenchmeyer]

Installed FF 3.6 today. Plus some recently changed KDE-libs from Opensuse's KDE stable repository (KDE 4.3.4).  

The flicker problem - which appeared under Opensuse 11.2, only - is apparently solved, now. Thanks, also in the name of my customers !!! 

In general there seems to be an overall performance enhancement. Excellent job.  

You can close the bug.   

Still, I wonder what made the difference for one and the same FF version under Opensuse 11.1 and Opensuse 11.2 and caused the strange behaviour of FF 3.5 under Opensuse 11.2.