345204 - Layout screwed up the first time you load a page, reloading fixes the layout

Status: NEW

(Core :: Layout: Floats, defect)

Description

[Max Santiago]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.4) Gecko/20060508 Firefox/1.5.0.4
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.4) Gecko/20060508 Firefox/1.5.0.4

If you go to visit the above websites, you'll notice that the content div's often go below the left div. It happens really frequently, you just have to randomly click here and there on those two websites (for example using the above main menu) and you'll notice the problem.
Verified with Firefox on XP and OSX 10.4. It happens at least on 6 computers. IE always renders correctly the pages.

Reproducible: Always

Steps to Reproduce:
1. open www.ischiagas.com or http://dev.cpl.it/nedweb
2. randomly click on the main nav links, or in the left nav
3. see the content div's go below the left div 80% of the times.
4. reloading the same page usually fixes the problem.
5. If you keep on reloading the same page it usually screws up after 3-4 tries.

Actual Results:  
I was presented with randomly rendered pages.

Expected Results:  
It should have represented always the same results, as other browsers do (Safari always renders those two websites correctly).

Comment 1

[Martijn Wargers (dead)]

Attachment: unminimised testcase

Unminimised testcase that triggers the bug by adding <script>document.body.offsetHeight;</script> somewhere in the page.

Comment 2

[Martijn Wargers (dead)]

Attachment: minimised testcase

Comment 3

[Martijn Wargers (dead)]

This seems similar to bug 257552, but is probably not exactly the same. Marking dependancy on that bug.
I can see the bug also in current trunk build.

Comment 4

[Max Santiago]

Hi there, I took a look at the minimised testcase, but I guess it's not only document.body.offsetHeight which screws layout.
www.ischiagas.com doesn't have that javascript anywhere, but firefox keeps on randomly rendering the right div below the left one.

Comment 5

[Martijn Wargers (dead)]

Max, the javascript I used is just a trick to trigger the layout screw-up, so we can get a reliable testcase that reproduces the issue.
There are certainly other ways which the layout screw-up can happen, which doesn't involve javascript.

Comment 6

[Martijn Wargers (dead)]

This is still an issue with a build after the reflow branch landed.