#1 Dragging node outside canvas area acts odd

[Christian Convey]

Try to drag a node outside of the canvas area. The
node refuses to leave the area, which is good. The
mouse can keep on going, which is also good.

But once the mouse starts dragging again in a direction
that's valid for the node to move, the node starts
moving again in sync with the mouse, even though the
mouse is no longer over the item.

Ideal behavior is that the item doesn't move again
(during the drag operation) until the mouse cursor is
again properly over the item.