You should have options under the advanced tab to change the cursor locks offset position on all 4 sides, not just x and y;
lets say you are playing a game in full screen, and dont want to move the mouse over the title bar, currently you can set y to about -25; which is fine and dandy except for the fact that now you cant get to the bottom 25 pixels of the window..
also it would be slightly less confusing if you used 'top, bottom, right, and left' for the name rather than X and Y

This change appears to be implemented in the (5.1.0 (beta 2), however i would like to mention that even though the latest X/Y are there, they don't currently do anything. (just an update, incase its a bug although its probably just still in the works )

This got me wondering, is there a changelog for the beta, or is that only available for the official releases?