On the right side of the toolbar, there are three options: automatic disappearance of the laser trails, and the manual remove all/erase laser trails option.

Explanation (optional to read): I’ve been using laser trails almost every time when I review because I can write on top of my written notes and annotated handouts to help me remember, but what’s frustrating about it is that it disappears so fast when I try to write multiple words of what I have just reviewed seconds before. I can’t use the regular pen and write above these papers of mine since they are annotated/written so my notes will be erased alongside the words I've just written from my review.