how to change layout of a XmFileSelectionBox?

[Peter J. Bismuti]

I have an application that uses a XmFileSelectionBox. It has the nasty habit 
of making the directory selection list very wide while making the file 
selection list very narrow. A hack was put in that places a file called 
"zzzzzzzzzzzzzzzzz.dat" in the current directory forcing the file list widget 
to become wide enough to accomodate it.
I was told to fix this problem properly, but I'm not sure how to do this.

Another thing I'm noticing that I don't understand is that in the file 
selection list, the absolute path is listed (directory plus filename, 
i.e. /home/me/data/zzzzzzzzzzzzzzzz.dat instead of simply 
zzzzzzzzzzzzzzzzz.dat.) How do I change this behavior?

Thanks in advance