Scythes answer to this:
Resizing is aspect ratio safe, the mouse cursor still can move on X or Y axis. Cosmetic issue that is inherent to Windows itself (OSX would never allow such a glitch!).
You see the same with a ton of video players as well. I was under the impression that users know what this is. I feared not allowing them to move the cursor even more will confuse them. Obviously I was wrong. Will change that.
https://forum.team-mediaportal.com/...features-and-fixes.114566/page-68#post-984552
http://www.pcworld.com/article/220222/Windows.html