Comment 15 for bug 869652

Region mode stops and waits for you to draw a rectangle with the mouse, so at the moment that KSnapshot grabs the screen contents, the mouse cursor would always be positioned at the very corner of the rectangle you just drew. KSnapshot also changes the cursor to a crosshair while you're doing this. That's why the patch disables the mouse cursor grabbing when in region mode.

I don't know how you'd make them compatible... stop and wait for a subsequent mouse click inside the rectangle you just drew?