It is possible to drag stitching points off the edge of the image.
Although these points are no longer visible, they can still affect the
stitching process.
It should not be possible to drag stitching points off the edge of this
image.
To delete points, first select them by clicking them on the image
itself or by clicking their entries in the list of stitching points on the
Wizard panel. You can use the SHIFT key to select multiple points.
Then type the Del or Delete key on your keyboard to delete the points.