animations sometimes stop and continue shortly after scrolling




6 years ago
6 years ago


(Reporter: tkohlmeier, Unassigned)


20 Branch

Firefox Tracking Flags

(Not tracked)




6 years ago
User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:19.0) Gecko/20100101 Firefox/19.0
Build ID: 20130215130331

Steps to reproduce:

I didn't find a way to reproduce this bug, yet. It does not happen just after a fresh Firefox start, Firefox has to be running for a while, before this problem occurs.
The problem is, that all kind of animations stop, like javascript or flash animations. After scrolling, the animation continues for a very short time.

I uploaded two videos to demonstrate the problem.

Video 1 (a flash animation on
This animation should normally continue infinitely.

Video 2 (a javascript animation on
As you can see, the clock stops and goes on for a short period of time after scrolling has finished.

My device is a Samsung Galaxy S2, running Android 4.0.4.

Actual results:

Animations stop.

Expected results:

Animations should continue infinitely.


6 years ago
OS: Windows 7 → Android
Hardware: x86_64 → ARM
Thanks for filing this bug.

I tried out the URL on my Nexus 4; I zoomed in and scrolled and the billboard kept rotating through the three offers and the timer still kept going fine. I tried this out on Nightly (03/04) and Beta (Fx-20). As you mentioned this happens sometimes, I haven't see this thus far. It would be good to know if you see this using Nightly ( for Android.

Comment 2

6 years ago
I tried Nightly (03/04) and just had the same problem again. It was working for one or two days without any problems, but now it happened again...
I think this is device specific, as my brother, who is using a HTC One X, never had this problem...

Comment 3

6 years ago
I just wanted to inform you that after upgrading to android 4.1.2 this problem still exists...
This sounds like something on the gecko side is not driving the compositor as it should be. When the user pans (and shortly after) we drive the compositor from java to paint the newly visible content and fade out the scrollbars, so that's why the animations animate. Maybe layout/graphics people will have a better idea of where animations are supposed to be triggering redraws and driving the compositor.
Component: Graphics, Panning and Zooming → Graphics
Product: Firefox for Android → Core
Version: Firefox 20 → 20 Branch
You need to log in before you can comment on or make changes to this bug.