Passing `true` as the third arg is only necessary if the event name is already whitelisted in `Y.Node.DOM_EVENTS`, which "MSPointerEnter" wouldn't be.

If the event name is changed to pointerenter, then it would make (some) sense to leave `true` here. But that would override the native behavior for pointerenter, deferring to the proxy event. This would be necessary for delegation, but not for direct subscription. I think this problem exists for mouseenter as well, so maybe it would be fine. Better to make the events smarter, but that's beyond the scope of this PR.