[GRASSLIST:4072] v.digit problem: unlabeled lines invisible

[cheg01 at attbi.com]

When I use v.digit to delete internal boundary lines in patched vector
files, I have a problem in the Window menu. It  will not display unlabeled
lines with the "U" command. It shows the set of labeled lines correctly but
when I try to show unlabeled lines (which should be the inverse set) it
shows nothing. I tried changing the background color but it did not help.
Any ideas?

Thanks.