In the case of {HEAD ~ trapping}, {TAIL ~ the movement} of the rear pane in the lowering direction is stopped and the rear pane is moved in the lifting direction  
In the case of { HEAD ~ trapping } , { TAIL ~ the movement } of the rear pane in the lowering direction is stopped and the rear pane is moved in the lifting direction
OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH