Thanks for the advice. I tried that and it worked pretty
well, but in trying that out I figured out what caused the problem.
All of my open apps in a maximized state occupying the entire
desktop, except for my company's app which I had resized to the
size I wanted to capture. Once I maximized the company app,
Captivate 3 listed it in the dialog box menu dropdown. Then, once
I'd selected it, I could resize the app window to the desired size
before starting the recording...