While pressing Shift key, Event.current.shift returns true only when moving the mouse. Otherwise returns false. That creates flickering in my editor windows when I try to draw things when Shift key is pressed. You can see that also in the Scene View using the move tool and pressing Shift key to activate the free move handle. Movement using the free move handle is also broken, the object moves but doesn't follow the mouse position (tested in a mac book pro retina display).