Hi there,
I make cave maps with Xtreme and I use lots of closed lines when I draw rocks and boulders. The final map is converted to a PDF. Recently I came across a gotcha. To check this:

1. Set up your drawing conditions so that an arrow head is selected.
2. Draw an open line. The line gets an arrow head, OK?
3 Draw a closed line. The line does not get an arrow head, OK?
So far so good.
4 Export to PDF.
5 Look at PDF.
BOING! GOTCHA. Both open and closed lines have arrowheads!!!!
6 The same effect occurs with tails.

When you have dozens of closed lines in your drawings this can come as a nasty surprise.

Comments are welcome.

Erik