Bug 144688 - Touch event timeout is flaky
Summary: Touch event timeout is flaky
Status: NEW
Alias: None
Product: WebKit
Classification: Unclassified
Component: UI Events (show other bugs)
Version: 528+ (Nightly build)
Hardware: iPhone / iPad iOS 8.2
: P2 Normal
Assignee: Benjamin Poulain
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2015-05-06 09:30 PDT by Rick Byers
Modified: 2015-06-30 07:57 PDT (History)
2 users (show)

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Description Rick Byers 2015-05-06 09:30:43 PDT
Repro on mobile Safari in iOS 8.3:
- Load http://rbyers.net/touch-timeout.html
- Set the delay to 800ms
- Try scrolling anywhere within the blue border box
- After a brief delay, the document scrolls up
- Scroll it back down
- Now just touch (without scrolling) within the blue border box
- The moment your finger goes down, the page moves up.  WTF?

Note that the behavior is quite dynamic.  If you try with the default 300ms timeout first, then the behavior will not reproduce after increasing the timeout to 800ms (you must reload the page to see the issue).

I'm trying to better understand how scrolling in Safari reacts to slow touch event handlers and I'm very confused (some notes here: https://docs.google.com/document/d/12k_LL_Ot9GjF8zGWP9eI_3IMbSizD72susba0frg44Y/edit#heading=h.5zfdv2co2oj).  Is the code for this public or internal?
Comment 1 Rick Byers 2015-06-30 07:57:30 PDT
I can no longer reproduce this reliably.  Ben and I discussed this offline and it sounds like there are definitely some bugs here with the timeout behavior making it unreliable.  Perhaps there should just be a fixed 1000ms timeout?  This is what we plan to try in Blink: https://groups.google.com/a/chromium.org/forum/#!topic/blink-dev/Y4ghiJy6Fss