onMouseLeave strange behaver when has disabled child element

[zombieJ]

Bug report.

Here is the demo: https://jsfiddle.net/qz3fytwe/1/

When <div> contains an disabled button. React can trigger onMouseEnter correctly in div but onMouseLeave not trigger when mouse on the button and move down out of the div.

I tried 15.4.0 & 15.6.1 in Chrome has the issue. Not sure whether it appear before that.

[zombieJ]

hi @gaearon, could you pls take a look?

[jquense]

Hi there, yes mouse events don't work on disabled elements generally, this is a browser implementation detail and not something easily addressable (if at all). There are already a few issues about these events and mouse events and some PRs attempting to make the behavior more consistent.

In all likelihood though, in the future react will defer to the behavior of the native events and their behavior which means they won't fire on disabled elements in some way.

[aweary]

@jquense in the example @zombieJ provided the leave and enter events are registered on the div containing the disabled button, not the button itself. In this case, I think it should be dispatching the leave event, since it dispatches an enter event and it works as expected with regular event listeners

[jquense]

Yeah the enter/leave traversal logic is implemented in terms of from/to elements. So yeah, unlike the native event react will drop events in odd places, because one of the elements being moved to or from is disabled, and so it's pair can't be accurately calculated. In the fiddle, leave works if you exit right from the button then down. It's missing the other directions because the surrounding div has no dimension around the button and so isn't firing mouseover/mouseout events (and the button fires nothing)

I meant to close with some refs to the previous issues:

#10109
#4251

The various PRs I have up will at least bring the behavior in line with the native events:
#10247
#9824
#10269

[Jony-Y]

@jquense seems like this will only be solved in 17.0.0 according to #11972

Is there some w/a for now for us to use?
EDIT
Mutated my HOC to use native event listeners with ref as a w/a

[RNachmanyAnyVision]

This issue still open.
We create native event listener (with ref) to avoid the problem.