You can lengthen or shorten edging by clicking and dragging its end points.
To change the length of edging:
Select the edging you want to lengthen or shorten. Grab handles are displayed at the center and ends of the edging.
Hover your pointer over the end
you want to stretch. The Lengthen cursor is displayed.
Click and drag to lengthen or shorten the edging, then release your mouse button. Example