fix: cursor changing on window move and resize

[eriedaberrie]

Describe your PR, what does it fix/add?

Fix inconsistent mouse cursor during window moving and also use the "corner"cursors during window resizing.

Is there anything you want to mention? (unchecked code, possible bugs, found problems, breaking compatibility, etc.)

The corner cursors might look kind of out-of-place if dragging from near the middle of the window, or from the wrong side when tiled? Not sure.

Is it ready for merging, or does it need work?

Yes.