This is a very easy fix:
About line 329 in FileBrowser.py, changed the line that reads
devices = psutil.disk_partitions()
to
devices = psutil.disk_partitions(all=True if OSNAME=="nt" else False)
Once this is done, mapped network drives on Windows show up properly. You don't want all=True on Linux, as that would get a bunch of non-useful items ('/sys/kernel/debug' and so on).