ComboBoxEntry question

["Edward A. Hildum" <Edward A Hildum nasa gov>]

I want a callback to run when an item in the dropdown box of a 
ComboBoxEntry is selected or when the Entry generates signal_activate() 
(new item or pick from a history list).  I've connected a handler to 
ComboBoxEntry::signal_changed(), and it gets called when items are 
selected, but it also gets called on every character typed in the 
Entry.  Is this the intended behavior?  It seems as though every 
Entry::signal_changed() generates a ComboBoxEntry::signal_changed().  Is 
there a better way to do what I want?

Thanks,
Ted