Update the caption when the group for a window changes.
tree09387ff59c594b9334e36901ef706b0e98dc306c
-rw-r--r-- 18004 COPYING
drwxr-xr-x - incoming
-rwxr-xr-x 1150 mktar.pl
drwxr-xr-x - patches
drwxr-xr-x - src