620548 - Pages scroll slowly when the document has a fixed background image

Status: RESOLVED DUPLICATE of bug 90198

(Firefox :: General, defect)

Description

[Ronny Orbach]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US) AppleWebKit/534.10 (KHTML, like Gecko) Chrome/8.0.552.224 Safari/534.10
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.13) Gecko/20101203 Firefox/3.6.13

Any page with a fixed background image scrolls noticeably slower in Firefox. I've created a simple test page for this for your convenience, but most twitter/myspace profiles would prove this as well.

Reproducible: Always

Steps to Reproduce:
The example page just does the following:
1. Specify a fixed background image for the document: body {background: url(example.png) 0 0 fixed repeat;}
2. Try scrolling
3. Change 'fixed' to 'scroll', refresh and try scrolling again. You'll notice the difference.

Comment 1

[Tim (fmdeveloper)]

Do you have hardware acceleration enabled? What graphics card do you have? Does turning off smooth scrolling make a difference?

(A couple related bugs: Bug 437178 [and related dups], Bug 361236, Bug 579794 and Bug 595400)

Comment 2

[Ryan VanderMeulen [:RyanVM]]

Firefox 3.6.13 doesn't support hardware acceleration, nor has it benefited from the substantial scrolling improvements made for Firefox 4.0.

Ronny, try Firefox 4.0 beta 8 (released today) and see what your experience is like.

Comment 3

[Ronny Orbach]

Hi,
The problem doesn't reproduce anymore in 4.0b8 (I think it did in previous betas) - That's good to see :-)

Anyway, I use "Mobile Intel 965 Express Chipset Family" - Don't have hardware acceleration.

Does the bug reproduce for other 3.6 users?

Comment 4

[Ryan VanderMeulen [:RyanVM]]

Slow scrolling with fixed backgrounds is a well-known issue going back a very long time. It will reproduce in 3.6 builds and will not be fixed for 3.6.x due to the very extensive nature of the work it took to fix the issue.

Comment 5

[Ronny Orbach]

Thanks for the clear reply, Ryan. It's a pity, but understandable.