When saving to a directory, pan does not provide the backslash after the
directory name. A subsequent "save to" a different directory, necessitates
appending the slash after the previous directory name, otherwise the user 
cannot properly navigate the ~/News/Pan directory structure.

e.g. 
1) Save 1st attachment to ~/News/Pan/kittens/ <--note the trailing slash.
2) Now wish to save the *next attachment* to a different subdirectory.
However, when I select "save attachment as" the dialog window shows
"~/News/Pan/kittens", *instead of "~/News/Pan/kittens/ . 
The user either has to add the trailing slash, *or* remove the last
(i.e. most recent) subdirectory name, in order to properly navigate the
Pan subdirectories.

This bug is consistent and reproducible.