I am trying to figure out the best way to force the open panel of a
Cocoa doent-based application to allow selection of folders. In some
situations the doent model I use can be constructed from the contents
of a Folder, and I would like to allow users to select a folder.
Validation of the contents (to see if they in fact form a doent)
would be done in an NSDoent subclass method.
I realize I could subclass NSDoentController, and implement my own
version of openDoent, but am wondering if this is the best way (seems
a lot to subclass ...