33602 - rapid clicking on scroll buttons causes drawing artifacts

Status: VERIFIED DUPLICATE of bug 31131

(Core Graveyard :: GFX, defect, P3)

Description

[kaldari]

Steps to Reproduce: On any scrollable page, click on one of the scroll buttons
in rapid succession.

Actual Results: Page scrolls faster than Mozilla can redraw, resulting in
artifacts at either the top or bottom of the page, i.e. each 'line'
(approximately 10 pixels) of screen may be repeated up to three times. The more
you scroll rapidly, the more artifacts build up. The display is rendered
correctly if you force the window to redraw, for example, dragging another
window over the affected window.

Expected Results: The page should render correctly once scrolling is complete
regardless of the means or speed of scrolling.

Build Date & Platform: M14 MacOS

Additional Information: Bug does not occur when scrolling with the arrow keys,
only when clicking on the scroll buttons.

Comment 1

[kaldari]

*** Bug 33603 has been marked as a duplicate of this bug. ***

Comment 2

[Adam]

I've seen this on every build. There is a delay in redrawing the content when
you scroll. This can be achieved in any way you can think of to scroll, I see
this when scrolling with the arrow keys as well. This is on a G4/450 so it's not
a hardware problem. Confirming and changing severity to normal from minor. This
might be more of an XPApps problem but I'm not sure.

Comment 3

[Kevin McCluskey (gone)]

I don't see any problems on WINNT with 4/7/2000 build. 
Don, can you take a look at this on the Mac?

Comment 4

[Adam]

This problem goes away (or at least is greatly diminished) when 
switching from Gfx widgets/scrollbar to native ones (in the Debug panel in 
Moz Preferences). Latest test on M16 4/14.

Comment 5

[Adam]

This might be that Moz actually scrolls too slow - it doesn't know what to 
do when you physically scroll so fast and it can't keep up? If so, might be a 
dup or related to 31131. (As reported earlier, turning OFF Gfx scrollbars 
alleviates this problem).

Comment 6

[dcone (gone)]

I think this is a duplicate,  Pierre is investigating this.

*** This bug has been marked as a duplicate of 31131 ***

Comment 7

[Adam]

Pierre commented in bug 31131 that it has "nothing to do with 33602." I'm going 
to leave as duplicate but adding verifyme so some brave soul can look at this and 
make a decision.

Comment 8

[Chris Petersen]

Marking verified dup of 31131.