We are now using the Prompt Container with a list to achieve this but it's pretty "clunky." It is difficult to resize the title within the Prompt Container. I found out that I could add spaces to the title but then it would not resize appropriately so we couldn't use that option. Hovering over a Prompt Container with a list gives a strange looking Tip with the word "Selections" and we can't seem to format that as well.
Although I appreciate the Prompt Container and the ability to add multiple controls, I'm hoping for a one object multiple select drop-down control at some point!
