In Engrave mode, each playing technique continuation line has two square handles, one at the start and one at the end. You can move these handles to adjust the graphical position, length, and angle of playing technique continuation lines.
If playing technique continuation lines cross system and frame breaks, you can move the line segments on each side of the break independently.
Moving playing techniques with continuation lines moves them both together, including any adjacent playing techniques and continuation lines in the same group. Moving continuation lines or continuation line handles moves the continuation lines independently of the playing technique.