This is from v5 - always annoying Thanks! Hannes
Try dragging it by the very top edge (this is fiddly) of the pop up window to a position that’s not so intrusive. I think I’m right in saying that Rhino will then remember this relative position for subsequent calls.
Be careful not to call it when the dimension being edited is near the edge of your viewport. This will force the pop up to a new relative position (somewhere near the centre of the viewport?) so you’ll have to set up the offset position again.