As it turned out, I am glad that I posted the programming problem here because it WAS directly related to what I was trying to do.
I'm happy to say that you were ALL right; however, Mark, you hit the nail precisely on the head ... and that explains why it worked once and not again.
Originally I had the box parented to the form. When I looked at it, though, it looked a little awkward, so I decided that I wanted the box to cover the entire screen (canvas - which I now know it's called) for a more professional look ... so I simply "enlarged" the box. That's when my problem started.
Apparently, when I enlarged the box, it lost parenting to the form (unbeknownst to me) and that caused the compilation error.
So - in order to put this to rest - and to know what I can and can't do ...
Is there any way I can change the color of the canvas?

I would be thrilled if I can - but, at least I have a middle-of-the-road solution.
Thanks!