227882 - slow scrolling causes row of pixels to disappear from text

Status: RESOLVED DUPLICATE of bug 152671

(Firefox :: General, defect)

Description

[kerrirah]

User-Agent:       Mozilla/5.0 (Windows; U)
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.5) Gecko/20031007 Firebird/0.7

When scrolling slowly through any web page, a line of text will often be painted
missing a row of pixels.  This makes the text look cut off (if the missing row
is the bottom row) or compressed (if missing a row from the middle). 
Highlighting some of the text in that line repaints the whole line as normal. 
This is the same symptom as Bug 217753, except that it happens for me using
Firebird under Windows XP so I wanted to report it here.  See that bug for pictures.

I've had this problem since I started using Firebird (pre-0.6).  It does not
occur if I scroll only with PageUp/Dn.  It also only occurs on my laptop which
has a higher DPI setting in Windows' Display properties (120 DPI).  If I return
it to the default (96 DPI) the problem seems to go away.

Reproducible: Always

Steps to Reproduce:
1. Go to a web page more than one screen in length.
2. Scroll down slowly using mouse wheel or arrow keys
3. Look for a line missing a row of pixels.

Actual Results:  
Text is missing a row of pixels during/after scrolling.

Expected Results:  
Text should look normal during and after scrolling.

Comment 1

[Jason Barnabe (np)]

WFM Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.6b) Gecko/20031206
Firebird/0.7+

Comment 2

[alanjstr]

Please provide more information, including URLs and screenshots.  Since this is
unconfirmed, I doubt it should block 0.8.

Comment 3

[Brian Earley]

I've never seen it on Windows XP, but I do see it all the tine on Linux.

The Linux build was 20040116

Comment 4

[alanjstr]

per ben on IRC

Comment 5

[psellhorst]

See also bug 152671.

Comment 6

[Fen Wu]

(Fen Wu, 02/24/04) Mozilla/5.0 (Windows; U; Windows NT 5.0; en-US; rv:1.5)
Gecko/20031007 Firebird/0.7

Follow-Up Tests: 
1. Go through the reproduce steps on
http://www.romanm.ch/ascii-bilder/ascii-asterix.htm (ascii picture)
2. Go through the reproduce steps on http://www.cnet.com/ 
Notice that there is not broken text during slow scrolling. 
Suggest try the following:
3. Go through the reproduce steps on a very slow PC.
4. Change the display setting (lower the refresh frequency, coarse the display
mode) and Go through the same reproduce steps.

Comment 7

[Kenn Munro]

It happens on my computer also: Red Hat 9, Mozilla 1.4, 1.5 and 1.6, ATI Mach 64
video card (4MB RAM), Athlon 750 with 512MB RAM.  Display resolution is
1152x864, 65K colours.  The problem goes away if I drop the resolution to
1024x768 or lower, but I can't live like that!

Not all web pages trigger the problem.  I dissected one of them and found that
the key piece was "font-size: 10pt;" in either the .css file or style tag.  By
removing that from the page the problem went away.  My test page is <a
href="http://kenn-michelle.ca:8080/temp/33089.html">here</a>.

Comment 8

[Doug Halamay]

I'd say this is a dup of bug 152671 and at least ten or twenty others.

See bug 134942 (tracking bug) for the complete list of single pixel error bugs.

Comment 9

[Mike Connor [:mconnor]]

agreed

*** This bug has been marked as a duplicate of 152671 ***