358936 - overflow-x:hidden rendering very slow.

Status: RESOLVED DUPLICATE of bug 317991

(Core :: Layout, defect)

Description

[Kevin Constantine]

User-Agent:       Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.8.1) Gecko/20061010 Firefox/2.0
Build Identifier: Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.8.1) Gecko/20061010 Firefox/2.0

Microsoft SQL Reports Server is generating reports that use the overflow-x:hidden tag in their style sheet.  These reports often have thousands of DIV's each with overflow-x:hidden enabled on them.  Rendering this page is extremely sluggish, and scrolling is even worse.  

If I change the tag to the following:
overflow-x:hidden - has problem  http://sinsystems.net/overflow-x-hidden.html
overflow-x:scroll - has problem  http://sinsystems.net/overflow-x-scroll.html
overflow:hidden - No problem  http://sinsystems.net/overflow-hidden.html
overflow:scroll - has problem. 

It seems like overflow-x:hidden is trying to render all of the scroll bars, but then hiding them while overflow:hidden is just not trying to render them.  I would expect that overflow-x:hidden would behave the same as overflow:hidden.

Reproducible: Always

Steps to Reproduce:
1.Go to above mentioned websites. Scroll up and down.  Notice the differences in speed.


Actual Results:  
overflow-x:hidden is sluggish - not expected
overflow-x:scroll is sluggish -expected
overflow:hidden is not sluggish - expected
overflow:scroll is sluggish - expected

Expected Results:  
overflow-x:hidden is sluggish - not expected
overflow-x:scroll is sluggish -expected
overflow:hidden is not sluggish - expected
overflow:scroll is sluggish - expected

Comment 1

[Martijn Wargers (dead)]

overflow-x: hidden means that the computed style of overflow-y gets overflow:auto.

Comment 2

[Martijn Wargers (dead)]

I suspect a fix for bug 352093 might improve this.

Comment 3

[kris dahl]

Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.1.4) Gecko/20070515 Firefox/2.0.0.4

I am able to reproduce.

This is a common problem with slow scrolling HTML reports generated in Micrsoft Reporting Services.  Remove the overflow-x CSS and report scrolls perfectly, renders slightly differently.  Change 'overflow-x' CSS to 'overflow', renders identically but scrolls quickly.

This is a duplicate of bug 317991.