Gtk::TreeStore question

[Bob Caryl <bob fis-cal com>]

In all *my* applications that display Gtk::TreeStore objects in 
Gtk::TreeView widgets display a triangular shaped "carat" that points to 
the right if the parent item is unexpanded and points downwards if it is 
expanded.  I see plenty of other applications running on my desktop that 
display "plus" (+) and "minus" (-) signs instead of the carats.  Since 
different applications run both ways under the same desktop manager, I'm 
wondering how I can get the "plus" - "minus" version.  Any ideas guys?


Thanks,

Bob Caryl