Slingshot provides rectangles (like the Xt Intrinsics' RectObj gadget), 
drag-and-drop support, images, icons and text, trees, lines, arrows... 
You can look at the documentation for the details, but here's a few
teasers:  there are new objects (clock, bag, box).  The grip and the
drawarea have had a few interesting features added.  The documentation
has been improved dramatically.  The drawtext can now be editible.

CAVEATS
-------

This is NOT an official or supported product of Sun Microsystems, Inc. 
This software has been developed to leverage other efforts, and it is 
being released because it is hoped others can get benefits from it too.  
However, there ARE bugs in this software which may never be fixed, and 
there is no guarantee of compatibility between releases.