From: Steve Youngs <youngs(a)xemacs.org>
   Date: Sat, 21 Jul 2001 11:04:09 +1000
   
   How do I put a button on a toolbar and have it show up at the right
   hand edge of the frame (if it's a top toolbar)?
Does this do it?
`default-toolbar' (buffer: *Hyper Apropos*, mode: Hyper-Apropos)
  ...
  Optionally, one of the toolbar-button-descriptors may be nil
  instead of a vector; this signifies the division between
  the toolbar buttons that are to be displayed flush-left,
  and the buttons to be displayed flush-right.
  ...
The default-toolbar is set in toolbar-items.el with:
(set-specifier default-toolbar initial-toolbar-spec)
-jeff