Don't prevent pointerdown if target is a form control

[perliedman]

This is WIP to attempt fixing #2699.

The current approach is to white-list some tag types and not call preventDefault if they're the target, more or less what @fnicollet suggests. This seems to fix the problem, but I can't say it's elegant.

The other alternative I've considered involves actually calling stopPropagation on every form element (like suggested by @danzel: #2699 (comment)) which is messy and something people are likely to not understand that they have to do.

Any better solution? @danzel, do you have any suggestions?

[danzel]

If the only time we need this is for pointer events, then this is probably an ok place to do it.
Definitely want a note explaining why though, cause it's a weird thing to do!

Could we do a prosthetic hand test?

I like that this is something that we handle vs forcing users to do it.

[perliedman]

I added a comment.

Not entirely sure if prosthetic hand can do this, I tried just very quickly to hack up something that touches a control, but couldn't make it actually open the control. @IvanSanchez what do you think, is this something we could prosthetic for?

[perliedman]

So, I removed the "DON'T MERGE" warning from the title. Given current feedback it seems like an ok approach, and fixes a real issue for IE11 users.

A test would be nice, but I haven't been able to get prosthetic hand to click on on a select control so far; don't know if I can expect it to do that.