Open Bug 657107 Opened 9 years ago Updated 1 year ago

Menu animation sluggish on


(Core :: DOM: Events, defect, P5)





(Reporter: lcf.vs, Unassigned)




(Keywords: perf)


(1 file)

User-Agent:       Mozilla/5.0 (Windows NT 6.1; WOW64; rv:2.0.1) Gecko/20100101 Firefox/4.0.1
Build Identifier: 4.0.1


I found a bug quite disturbing, visually ...

Reproducible: Always

Steps to Reproduce:
1. Visit my personal website
2. Click on the red tab
3. Wiggle the mouse

Actual Results:  
Until you move the mouse, Javascript timeouts seem to freeze.

Expected Results:  
As timeouts have a process detached from events, as is the case in Chrome and IE
Version: unspecified → 2.0 Branch
So there is a red down arrow on the left side.
If I click that, there is an animation which shows the the menu.
The behavior seems to be the same on Fx4.0.1 and latest Chromium.
(I tested on Linux)

What exactly is the problem you see? Fx not showing up the animation?
(Opera 11 seems to have some problems when hovering over the menu items.)

Under Chromium, the animation is fluid, even if you move the mouse during this animation.

In Firefox, this is not the case, the animation is running but if you move the mouse, the animation it is chopped.
Version: 2.0 Branch → unspecified
Please leave the version as is
Version: unspecified → 2.0 Branch
Firefox 3.5.x on Windows XP (not sure the last digit, because I'm not training today)

Firefox 4.0.1 on Seven 64 (at home)
Version: 2.0 Branch → unspecified
Please, just leave the version as the latest affected version, Gecko 2. Don't change it please
Version: unspecified → 2.0 Branch
I don't change it, I tested on these 2 versions, one to my formation center, the other at home.

Check on the version of your choice ;)
Version: 2.0 Branch → unspecified
Not knowing if my explanation to you yesterday was clear enough, I'll put it another way.

The problem lies in the fact it appears that there when Firefox detects an event related to the mouse, it is paused timeouts.

In my opinion, this has no rationale, if one wanted such a behavior, it should be generated by the script and not by default the browser.
Firefox does not pause timeouts when it is handling mouse events.

So far I haven't manage to reproduce this. I've tested on Linux and Windows7
(I'm using nightly builds for testing.
The animation stays smooth even if I move mouse over the animated menu.

Do you happen to have some addons which might slow down browser?
Skype's addon for example?

I have only 2 addons, Firebug 1.7.0 et Web developper 1.1.9.

If you move your mouse when the ladder falls (at the beginning of the animation), don't you see slowdowns?

PS: Nightly has big problems rendering of SVG ... o_O
(In reply to comment #11)
> If you move your mouse when the ladder falls (at the beginning of the
> animation), don't you see slowdowns?

> PS: Nightly has big problems rendering of SVG ... o_O
Please file a bug for the problem.
(In reply to comment #12)
> (In reply to comment #11)
> > If you move your mouse when the ladder falls (at the beginning of the
> > animation), don't you see slowdowns?
> No.
check this video sample:

> > PS: Nightly has big problems rendering of SVG ... o_O
> Please file a bug for the problem.
Always unconfirmed?
I haven't managed to reproduce the problem.
Maybe someone else can.
Keywords: qawanted
Each of my friends (+ / -30 people), to whom I showed the start site reported to me, in Firefox, the animation is choppy, as soon as you move the mouse.
Attached image Screenshot 1
Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:7.0a1) Gecko/20110621 Firefox/7.0a1

The animation seems really fluid - no problems there.

Another thing concerns me - the text-area fields from the menu are too long and they go out of the designated menu area. I tried this on both Opera and Chrome and they show the areas withing the borders of the menu. See Screenshot 1 for a better understanding.
Reproducible on Mozilla/5.0 (Windows NT 6.1; rv:6.0) Gecko/20100101 Firefox/6.0 (beta 5)
and also on
Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv: Gecko/20110803 Firefox/3.6.20

Setting resolution to NEW.
Ever confirmed: true
Also reproducible on Mozilla/5.0 (X11; Linux x86_64; rv:7.0a2) Gecko/20110809 Firefox/7.0a2

@Lcf.vs could you please provide a minimized test case to attach to this bug?
OS: Windows 7 → All
Hardware: x86_64 → All
Summary: [Unexpected event] → Menu animation sluggish on
Summary: Menu animation sluggish on → Menu animation sluggish on

Thanks for your interest on these bugs. :)

Personally, I do not have this bug button too large, however, it allowed me to better understand the origin of the slowdown in the animation.

This slowdown occurs when moving the mouse over an item that was added a clipPath.


If you move fast enough the mouse cursor over the red square, as it descends, it is altogether stop the animation!
I couldn't find this website anymore:, while trying both the latest Nightly (20130111030906) and Chrome.

I did however managed to go to, but I couldn't find the animation that causes the issue. 

Is this issue still reproducible? Is there another URL I can test with?
Flags: needinfo?(lcf.vs)
Yeah, sorry...

The current URL :

Thanks for your interest.
Flags: needinfo?(lcf.vs)
(In reply to Lcf.vs from comment #22)
> Yeah, sorry...
> The current URL :
> Thanks for your interest.

Thank you for your answer. After clicking the red tab, I can confirm that the animation works slower than it does on Chrome.

Tested on the latest Nightly.

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:21.0) Gecko/20130113 Firefox/21.0
Build ID: 20130113031019
Using the same Nightly as in commment 23, I've noticed another issue, which I logged in bug 830260 .
Mozilla/5.0 (X11; Linux i686; rv:25.0) Gecko/20130730 Firefox/25.0
Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:25.0) Gecko/20130731 Firefox/25.0
Mozilla/5.0 (Macintosh: Intel Mac OS X 10.9; rv:25.0) Gecko/20130731 Firefox/25.0

Tested on latest Nightly (buildID: 20130730030204)
On Mac OS X 10.9 the animation is as fast on Nightly as in Chrome, Opera, Safari.
On Ubuntu 12.04 x32 the animation is as fast as on Chrome, and faster then Opera.
On Windows 7 x 32 the animation is two times slower on Nightly then Chrome, Opera, IE.
Keywords: qawanted

Move all DOM bugs that haven't been updated in more than 3 years and has no one currently assigned to P5.

If you have questions, please contact :mdaly.
Priority: -- → P5

Does it still reproduce?

Flags: needinfo?(bogdan.surd)
Keywords: perf
Flags: needinfo?(bogdan.surd) → needinfo?(bogdan.maris)


I attempted to reproduce this issue and the provided websites on which the issue was present are no longer available.

Flags: needinfo?(bogdan.maris)
You need to log in before you can comment on or make changes to this bug.