----------------------------------------------------------------------

Some widget sets have a widget particularly for this purpose -- a
WorkSpace or DrawingArea which doesn't display anything but lets your Xt 
application know when it has been re-exposed, resized, and when it has received
user key and mouse input. 

The best thing to do for other widget sets -- including the Athena set 
-- is to create or obtain such a widget; this is preferable to drawing into a 
core widget and grabbing events with XtAddEventHandler(), which loses a number 
of benefits of Xt and encapsulation of the functionality .  

The publicly-available programs xball and xpic include other versions. 
The Display widget in the XG library (libXG-2.0.tar.Z on ftp.x.org) provides a 
generic way of drawing graphics in a widget.

The Athena Widget manual (mit/doc/Xaw/Template in the R5 distribution) 
includes a tutorial and source code to a simple widget which is suitable for 
use. 

The Free Widget Foundation set contains a Canvas widget.