Creating Question Pools with Existing Questions

Hello (new) friends!

Stumped on a question pool issue. It may be something simple, but I am unable to populate question pools with existing questions.

I've created a question pool (and then a second, just to be sure), and am unable to right click on quiz questions and add them to the pool. As you can see, the slides in the film strip are questions (note grad-cap icon).

Any ideas? I'm using the latest release of Captivate 11.

In other blogs, it seems there is supposed to be an option in the dialog box there -- unless that's been deprecated.

Thank you in advance for your help!