I have a serious issue with up-events triggering unexpectedly on IE11 on windows phone.
It doesn't matter wether I use mousedown/up, pointerdown/up or touchstart/end. When I press and hold I get a down and after some hundred milliseconds I get the up event even though I am still holding on the screen.
It also trigger several "move" events before the up occurs.
Everything works as intended when I press and move around a bit. It's just pressing and holding that doesn't work.
The problem is reproducable in small scale tests and I have tested it several times on two different phones, both Lumia 930, one with preview for developers and one without.
I also have a problem with the javascript events and html rendering excecution being horribly slow on the lumia 930, compared to older android phones or even the even older iphone 4s.