How to remove destructive free-hand line?

[pttbltmtg]

Hi,

I just started using this program, but I don't know how to remove free-hand lines once they're drawn on destructively (Command+D), I know they can also be drawn using nondestructive (Command+B), but for some reason they always go away when I close and reopen the file even though I saved.

Is there a way to erase or modify a CMD+D line?

Thanks,
Max