In Windows 8.1 Update 1, Microsoft introduced a behavior where if you happen to have multiple displays and move the mouse pointer over to the other monitor while dragging a window for example, it blocks them at the corners. You have to move it fast in order for the mouse to not stick. This stickiness of the mouse pointer was a Windows 8 feature which could be disabled by a Registry tweak. Unfortunately it doesn't work in Windows 10. However I found a workaround for this.
In Windows 8.1 Update 1, if you have multiple monitors, you may have observed a strange behavior of the mouse pointer. When you try to move the mouse pointer across to the other monitor, it sticks at the edge of the screen. If you move the mouse pointer fast, it goes over successfully to the other display. This is a not a bug, it's a feature. Let's see how to fix it.