'Flag' at the beginning of a score
I admit that I'm embarrassed, as I've been asking what seems to be too many newby questions lately, but this one puzzles me. as I don't even know what terms to search for.
Suddenly this evening I have a blue line at the beginning and end of a score with a flag at the top. This prevents me from replaying from a selected point in a score; I can only replay from the beginning.
I've tried to right-click (Windows) on the offending item to see its attributes, but to no avail. I can't see what it is, I can't delete it, and I have no idea what it's called in order to search for help. I just want it gone.
Can someone identify what it is, its purpose, and how to remove it?
Many thanks from someone who probably is sucking up too much of other people's time.