This is files bar from OffiX --- part of desktop package with 
DND Drag & Drop protocol support. Very simular to Mac.

This is as file manager based on xfm. It provides virtually all of the
features that you would expect in a file manager -- move around your
directory tree in multiple windows, move, copy or delete files, and launch
programs with simple mouse operations.

WWW: http://leb.net/offix/