Currently, if I select several folders, then right-click and choose
properties, Nautilus will open a properties window for each folder.
Instead, it should do this: First it would open a dialog that asks simply:

Shall I
   () Open a property window for each folder
   () Open one property window for all folders

The options above could use some rewording. The first option is what
nautilus currently does. The second one produces a properties dialog that
summaries all the folders. In the "Basic" tab, you'll only have the
"Contents" and "Custom Icon" buttons. The "Share" tab is unchanged. The
"Permissions" and "Emblems" tab should also work, but will need a little
change.

In Windows, checkbuttons have a third level besides on and off - a half-way
between state that signals that this checkbutton is on for some things and
off for others. Does Gtk+ have this? This would be used in the "Emblems"
and "Permissions" tabs to indicate so-and-so is on for some folders, and is
off for others. Clicking checkbuttons toggles 'em between "on for all",
"off for all", and "back to the half-way state that everything was".