953066 - iframes may trigger mousemove event just *after* becoming invisible

Status: UNCONFIRMED

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

Description

[matteo sisti sette]

User Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/31.0.1650.63 Safari/537.36

Steps to reproduce:

1. Go to http://jsbin.com/owOgoDuy/1
2. Open the JavaScript console
3. Click on the "Toggle" link
4. While the iframe with the man image fades out, move the cursor over it. 
5. Keep moving the cursor frenetically for at least one second (i.e. a little bit longer than it takes for the iframe to become invisible)


Actual results:

While you move the mouse and the iframe is visible, you get printings of mouse coordinates in the console, like:
12,34
32,23
24,26
...

At the very moment when the iframe disappear, the last printing may look like this:
34,56!!!!!

This is not systematic. Sometimes the last printing is without the "!!!!" as expected.
So retry it a few times by clicking the "Toggle" link and repeating steps 1-5.

The "!!!!!" are printed if the iframe is not visible when the mousemove event is triggered. Something that should never, ever happen.


Expected results:

You should never see any "!!!!!" in the last printing.

Google Chrome is a very similar bug
https://code.google.com/p/chromium/issues/detail?id=330620
(but it is 100% systematic and it triggers even a spurious mousemove event when the iframe becomes invisible even if the cursor is not moving)


I have tried to isolate the issue into a smaller example which does not involve iframes
http://jsfiddle.net/W3NB5/4/
but this does NOT reproduce the issue.

Comment 1

[Firefox Bug Husbandry Bot]

https://bugzilla.mozilla.org/show_bug.cgi?id=1472046

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.