How can you add a drop-down list within a scroll panel

Hi everyone,

I'm working on a project (in Articulate 360) where I'm simulating a workflow in a software program.

I need to allow users to scroll down a page, and then within that pages choose a selection from a drop-down list.  I've been able to recreate most of the functionality within a scroll panel, but drop-downs seem impossible. Normally I use layers to create drop-downs, but you can't have layers within a scroll panel.

I would love to hear your ideas!