Videopad 11.55
I somehow got it into a state where there appeared to be a marker of some kind at a point in the timeline,
and then, no matter what I tried to do, putting my mouse pointer anywhere on the timeline, it would
then select the section from that mystery point to the cursor, expanding or contracting as the
mouse pointer moved left or right. This is the same behavior if you put your mouse on the red cursor
and drag left or right, but in the weird case, without holding down any mouse buttons.
Moving off the timeline, clicking the timeline, changing to another sequence, none of that helped.
Finally, I saved the project, closed Videopad, and restarted it, and then the problem was gone.
What happened there?