Hi, I have often wondered about this. At times, I simply go through and delete the line, refresh, repeat. Annoying at best. I just tried using the delete double command, but it doesn't seem to work.
Hide does work to remove duplicated lines, using Save Image as Roger pointed out.
I used these settings, in Options with F2 Delete Dbl. & F3 Ignore Color, and Hide F3 Save Image & S5 Active ON, you can get a new layer with duplicated lines removed, and even shorter lines with the same or different Z settings under longer lines get removed.
DataCAD 22.02.14.02 BETA on my own build Gigabyte MOBO rack mounted Windows 10 Pro 22H2 x64 i7 920