Jim,

>Tools-->Options-->Controls lists lots of ActiveX controls available to me.
>
>However, I can't find out how to learn what any of these actually do (can be used for).

the list shows You all ActiveX and COM that are installed on Your machine.
I quess most of them belong to specific applications and are not intended
to be for Your Use. Some of them are not only not documented but You will
also not be able to use them in a development context as You would need license
files or keys to make them work at all.

However most of the MS - stuff can be used well. You might find info in
the MS-Knowledgebase. And for the ImageList, TreeView, ListView You even
have info in the VFP-Help.