Bug 137851 - REGRESSION (Yosemite): Embedded WebView flickers position: fixed elements during rapid scrolling events
Summary: REGRESSION (Yosemite): Embedded WebView flickers position: fixed elements dur...
Status: NEW
Alias: None
Product: WebKit
Classification: Unclassified
Component: Layout and Rendering (show other bugs)
Version: 528+ (Nightly build)
Hardware: Mac (Intel) Other
: P2 Critical
Assignee: Nobody
URL:
Keywords: InRadar
Depends on:
Blocks:
 
Reported: 2014-10-18 07:17 PDT by Michael
Modified: 2015-02-03 12:41 PST (History)
5 users (show)

See Also:

Attachments
Video demonstrating the bug (249.00 KB, video/quicktime)
2014-10-18 07:17 PDT, Michael 		no flags Details
Sample HTML page (507 bytes, text/html)
2014-10-18 07:18 PDT, Michael 		no flags Details
Reduction (35.13 KB, application/octet-stream)
2015-02-03 12:41 PST, Scott Kyle 		no flags Details
View All Add an attachment (proposed patch, testcase, etc.)

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Description Michael 2014-10-18 07:17:52 PDT 
Created attachment 240063 [details]
Video demonstrating the bug

Using an embedded WebView inside of an application using the WebKit framework produces 
flickering of position: fixed elements while rapidly scrolling the page. This behavior 
did not exist until OS X Yosemite, Developer Preview #5 — it is believed to be a result 
of: https://bugs.webkit.org/show_bug.cgi?id=135135

Steps to Reproduce:
1. Create an application with an embedded WebView that uses the version 1 of the WebKit 
   provided WebView infrastructure. Not WKWebView. Normal WebView.
2. Load an HTML page with contains a position: fixed element
3. Scroll rapidly to produce flickering behavior

Expected Results:
The expected result is that the element stays statically fixed with no flickering during 
scrolling events

Actual Results:
position: fixed HTML elements flicker during rapid scrolling events

Build Date & Platform:
First seen: OS X Yosemite, Developer Preview #5
Last tested: Intel Mac OS X 10.10, AppleWebKit/600.1.25

Notes:
This bug report is a copy of: <rdar://problem/18211024>
Comment 1 Michael 2014-10-18 07:18:12 PDT 
Created attachment 240064 [details]
Sample HTML page
Comment 2 Simon Fraser (smfr) 2014-11-06 14:10:36 PST 
A workaround for this bug is to make the WebView layer-backed.
Comment 3 Scott Kyle 2015-02-03 12:41:17 PST 
Created attachment 245955 [details]
Reduction

This is still an issue on OS X 10.10.2. The attached reduction has a layer-backed WebView that exhibits this bug when scrolling back and forth NYTimes. You can enter `https://www.facebook.com` to see it very prominently there when scrolling up and down as well. This has resulted in many negative reviews for my app.