Frank, Move the magnifying glass on the Panorama Editor window to a place on the edge of the panorama image where you want to drag the crop bar down to. Then grab the crop bar and drag down to the position you want and as you do this, you will see the cursor position in the Detail Viewer move indicating exactly where the crop line is positioned, though not the yellow bar itself. When you release the mouse button, the crop will be actioned after a few seconds. It would be nice to see the yellow bar there too but the above technique may be adequate for your purposes.
John