RH 7.0 Final.

Sawfish Workspaces configuration (from Gnome Control Center) is a bit odd. 

If you add columns or rows, and click 'try' the changes are applied
immediately.
These vales can go up and down.

If you add Workspaces, and click try, more workspaces will appear. 
_However_,
when you decrease the number of workspaces,  the changes won't kick in. 
You have
to log out (or equiv.) to activate changes.