There is a bug with XenForo popups in IE Edge with touch screen: clicking popup control opens popup and immediately closes it, as if it was clicked twice.
You can see it by clicking any popup link in default style without any add-ons. Easiest way to test is to click sub-forums arrow below "XenForo Suggestions" forum on this very forum. It will open for a second then close.
Found what's causing it and solution. Problem is XenForo doesn't detect computer as touch screen, even though it has touch screen, so XenForo.PopupMenu toggles menu on mouseover event.
IE doesn't use touchstart event, therefore current detection doesn't work. However IE has navigator.maxTouchPoints property with value 0 for devices without touch screen and above 0 (10 on my laptop) for device with touch screen. IE Edge uses unprefixed property, old IE uses prefixed property.
Solution: in xenforo.js find
_isTouchBrowserVal = !!('ontouchstart' in window);