Open Bug 503732 Opened 15 years ago Updated 2 years ago

scrollbar arrow buttons scroll at a slower pace if smooth scrolling is enabled (regression in 3.5)

Categories

(Core :: Web Painting, defect)

1.9.1 Branch
x86
Windows XP
defect

Tracking

()

People

(Reporter: canon138545, Unassigned)

References

()

Details

(Keywords: perf, regression)

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1) Gecko/20090624 Firefox/3.5
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.1) Gecko/20090624 Firefox/3.5

See "Steps to Reproduce"


Reproducible: Always

Steps to Reproduce:
1. Go to a web page that is long enough to be scrolled for a few seconds.
2. Using a stopwatch and the vertical scrollbar GUI arrow buttons (not the keyboard arrow buttons), time how long it it takes to scroll from the top to the bottom of the page with smooth scrolling turned OFF.
3. Repeat the previous step with smooth scrolling turned ON.
4. Optionally repeat steps 1 through 3 with Firefox 3 to see how this has changed from version 3 to version 3.5.

Actual Results:  
Actual results will vary but the point is that the arrow buttons are significantly slower when smooth scrolling is turned on. For example, using 1024x768 screen resolution and the 9 July 2009 revision of http://en.wikipedia.org/wiki/Bugzilla, I get around 4.8 seconds with smooth scrolling turned off and around 8.1 seconds with smooth scrolling turned on.

Expected Results:  
The scrollbar arrow buttons should scroll at a reasonable speed when smooth scrolling is turned on, as they did in version 3. Ideally, if it takes 4.8 seconds to scroll from top to bottom of a particular page with smooth scrolling off, then it should take in the neighborhood of 4.8 seconds with smooth scrolling on.
Mozilla/5.0 (Windows; U; Windows NT 6.0; en-US; rv:1.9.1.1pre) Gecko/20090710 Shiretoko/3.5.1pre

I can imagine that de video card has to do more while scrolling smoothly, but you say it's a regression. Personally I see no difference (on this computer).
Keywords: regression
Product: Firefox → Core
QA Contact: general → general
Version: unspecified → 1.9.1 Branch
Flags: blocking1.9.2?
Status: UNCONFIRMED → NEW
Ever confirmed: true
Flags: blocking1.9.2? → wanted1.9.2+
Component: Layout: View Rendering → Layout: Web Painting
Severity: normal → S3
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