NSPopupButton itemAtIndex:

[Rob Burns]

This is from older Apple docs. The OpenStep docs say something similar.

itemAtIndex:

   - (id <NSMenuItem>)itemAtIndex:(int)index

   Returns the list item at index. If there is no item at index, this 
method
   returns nil.

In GNUstep it appears to raise an NSRangeException if there is no item 
at the given index.

Rob