There is a new bug that won't let the mouse to the other screen unless you move the mouse quickly across the monitor edge.
I can confirm this issue. I have 3x monitor and I just updated to W8.1 update ~1 hour ago.
As soon as I went to desktop and opened something, I was trying to move it to another monitor and faced this issue.
Behavior BEFORE W8.1 update (i.e., w8.1):
there is a small area from top and bottom (~100px height) of each left/right edge of all monitor where your mouse cursor will get stuck if you are moving it slowly. This has been done (on Windows 8.1) to help activate charms for mouse users.
Behavior AFTER W8.1 update (I.e., w8.1u):
1. The stickiness level has been increased a little
2. The small area (~100px height) has been changed to 100%.
#2 is the real culprit. This is almost a deal breaker. I am having SERIOUS issues moving windows from one monitor to another. And often, the cursor would just get stuck in the edge while going from one to another monitor just because im not moving it really fast.
Anyone else facing this issue? None of the kb/m enhancement in win 8.1 update 1 helps me in any way. But now this stupid issue is really bringing down my productivity