Iwidgets is a "mega-widget" set built using itk.  It includes
a set of megawidgets, installed in %%PREFIX%%/lib/iwidgets4.0.1
(and symlinked to %%PREFIX%%/lib/iwidgets), a set of man pages
describing the various widgets, some scripts in
%%PREFIX%%/lib/%%IWIDGETS%%/scripts and some demo files in
%%PREFIX%%/lib/%%IWIDGETS%%/demos.  Run the demos in X windows by
using wish (E.g. wish8.4 %%PREFIX%%/lib/%%IWIDGETS%%/demos/checkbox)

All the man pages are installed as iwidgets_example.  If you search
man for widgets, you will get the Tk widgets.  To see the man pages
for iwidgets widgets, type man iwidgets_toolbar (for example.) There
is also a set of html documentation pages installed in
%%PREFIX%%/lib/%%IWIDGETS%%/demos/html that may be helpful.
Look at iwidgets4.0.0UserCmds.html for a list of the user commands
that are available to you.

Finally, you may want to read iwidgets.ps (use a Postcript viewer),
installed in %%DOCSDIR%%, which is a comprehensive
explanation of iwidgets.