I removed the debugging print statements before I posted here. Everything is set as I expect it to be within this section of code... but the popup doesn't wait... therefore, my calling window/program doesn't ever get the value I have selected.

To get this project off of my plate I just grew my original window and placed the list into it. But I still have to understand what I'm doing incorrectly because, even though I don't have to use Tk very often, I still have some programs I've inherited that I must maintain. And they're chock full of pTk stuff.

Thanks for the help.