I refer to solved bug "xdg-open can't open torrent magnet links in xfce" https://bugs.freedesktop.org/show_bug.cgi?id=47172.

This was caused by the xdg-open script failing to detect an Xfce4 session because it was looking for "xfce" or "xfce4" in the environment variable DESKTOP_SESSION. It has now been modified to look for "Xfce Session" too.

The chaps at Portland asked me to point out that changes in the value of this variable could cause problems for applications that use it as a test.

So this is more of a polite request than a bug, but I couldn't find a mailing list so I've put it here and marked it "trivial", hope that's ok.