Bug 91348

Summary: REGRESSION (tiled drawing): Page’s scroll bars flash with each character you type in a textarea (affects Wikipedia and YouTube)
Product: WebKit Reporter: mitz
Component: WebCore Misc.Assignee: mitz
Status: RESOLVED FIXED    
Severity: Normal CC: cdumez, d-r, eric, mifenton, sw0524.lee, tkent, webkit.review.bot
Priority: P1 Keywords: InRadar, Regression
Version: 528+ (Nightly build)   
Hardware: Unspecified   
OS: Unspecified   
URL: data:text/html,%3Cbody%20style=%22width:%20200%25;%20height:%20200%25;%22%3E%3Ctextarea%3E
Bug Depends on: 91363    
Bug Blocks:    
Attachments:
Description Flags
Return early from ScrollableArea::scrollPositionChanged() if the scroll position doesn’t change
none
Call notifyContentAreaScrolled() from scrollPositionChanged() only if the scroll position changes aestes: review+

Description mitz 2012-07-15 12:12:10 PDT
<rdar://problem/11875795>

When typing inside a textarea, the page’s main scroll bars flash with each character typed.

To reproduce:
1. Navigate to the URL
2.Click inside the textarea and type

With each character typed in the textarea, the page’s horizontal and vertical scrollbars flash.
Comment 1 mitz 2012-07-15 12:16:28 PDT
Created attachment 152464 [details]
Return early from ScrollableArea::scrollPositionChanged() if the scroll position doesn’t change
Comment 2 mitz 2012-07-15 13:16:04 PDT
Fixed in <http://trac.webkit.org/r122681>.
Comment 3 Chris Dumez 2012-07-15 22:16:28 PDT
After this patch the following test started failing on EFL port:
css3/flexbox/flexbox-overflow-auto.html

http://build.webkit.org/results/EFL%20Linux%2064-bit%20Release/r122681%20(2660)/css3/flexbox/flexbox-overflow-auto-diffs.html

The reason for the failure seems to be that some of the scrollbars are no longer positioned at the extremities.
Comment 4 Chris Dumez 2012-07-15 22:34:35 PDT
I filed Bug 91359 for the regression on EFL port.
Comment 5 mitz 2012-07-15 22:35:34 PDT
(In reply to comment #4)
> I filed Bug 91359 for the regression on EFL port.

Thank you. I can reproduce this in OS X as well if I disable overlay scroll bars.
Comment 6 Dominik Röttsches (drott) 2012-07-16 00:09:56 PDT
This causes the EFL and GTK Debug Bots to fail due to an assertion in ScrollableArea::scrollPosition() being hit, cmp. 
https://bugs.webkit.org/show_bug.cgi?id=91359#c4
Comment 7 WebKit Review Bot 2012-07-16 00:14:30 PDT
Re-opened since this is blocked by 91363
Comment 8 mitz 2012-08-04 22:32:15 PDT
Created attachment 156551 [details]
Call notifyContentAreaScrolled() from scrollPositionChanged() only if the scroll position changes
Comment 9 mitz 2012-08-04 22:56:49 PDT
Fixed in <http://trac.webkit.org/r124714>.