Blender Git Loki

fix for window join action being interpreted as a split.

The limit for dragging a gesture on an area corner was smaller then the area hot-spot,
so you could click on the right-most side of the bottom-left corner, drag left - pass the gesture threshold and still be in the same area. so a motion intended as a join would register as a split.
Happened more with high DPI values. fix by ensuring the drag limit is always higher then the hotspot.