How to add controls to the client region of a tabstrip?

You should be using a MultiPage control instead of a TabStrip if you want to embed controls within it.

I've already done that, actually, because somebody mentioned on some random google hit that multipages are more versatile.

But I was just curious how to get a tabstrip to work at all, since my tabstrip isn't working at all.

Someone will no doubt disagree with me, but tab strips must be the least useful control Microsoft has dreamed up.

Some places I've looked talk about setting a "container" property through VBA, but that's at run-time, and can't be designed (except maybe using the immediate window...?).

There is no "Container" property displayed in the Properties window in VBA when I select my textbox... there's no "Container" property listed for any controls I can see in VBA's help... and the VBA help entry "Container Property" is telling me that it's a read-only property.