Mouse events do not participate in gestures on touch-enabled devices

[grayrest]

Some devices (like Windows 8 PCs) are touch enabled... but they also have a mouse! The result of only listening to touch events when feature detecting is that drag and drop for these devices seems broken using mouse.

The patch seems to correct the issue and not break anything. The PR is mostly to make you aware of the issue.

[tilomitra]

Thanks for this pull request! This is something that I am looking into currently. I'll report my findings back here.

[tilomitra]

Hey, this fix actually won't help under the hood because these arrays aren't iterated on by any module AFAIK. I'm going to go ahead and close this, but you can follow this ticket for progress:

http://yuilibrary.com/projects/yui3/ticket/2533158

[grayrest]

We're using this in production at Squarespace and support has confirmed the fix with customers. The YUI .on methods can take an array as the first argument to register the function as the handler for all events in the array. There's no other iteration happening.

[tilomitra]

@grayrest You're right re. the .on() method accepting the array, so that works. I think this is a good start, but the individual modules (event-tap, event-gestures) still need a way to prevent the second listener from firing the callback in a touch environment.

For example, if you're on a device that uses both mouse and touch input, and you touchstart on a node, the mousedown that is triggered should not fire the callback again.

Does that make sense? Did you guys tackle that issue at Squarespace by any chance?

[grayrest]

The only fix I've put in place is the one included here. A lot of interactions in our system are event-gesture by way of DD and this patch doesn't seem to trigger taps there. I also haven't received any bug reports about spurious taps but most taps in our system are idempotent. I just checked a few that aren't and we're double triggering from what looks like the 300ms fallback click trigger. Haven't attempted a fix.

[doulostheou]

I'm not sure if I have anything to add to this or not, but I thought I would comment on my experience using Windows 8 and the dd-plugin module. Using Internet Explorer 10.0.4, the mouse will allow me to drag and drop with no difficulties at all, and I can also drag and drop with my finger. Using Google Chrome 26.0.1410.64m, I can drag and drop with my finger, but not the mouse.

[tilomitra]

@doulostheou That makes sense. In IE10, we use the MSPointer API which abstracts touch and mouse events. In Chrome, you need to explicitly set two listeners - one for touch, and one for mouse. This is what the dual-listener issue references, and that's what I'm working on to fix for this sprint.

[tilomitra]

Refer to this pull request: #986