Objects Need to Stay on Screen

I have a slide I'm developing for a course in which I have several dropdown lists. I need to have the user select a value from each of the lists then I need to have the selected value continue to be displayed on the screen when the next dropdown list is displayed.

I have each of the dropdown lists in a separate layer, and each of the elements on each dropdown is in a separate layer. When the user clicks the dropdown arrow to open the list, the dropdown list is displayed and each item on the list is highlighted separately. When an item on the dropdown list is selected, the list is hidden and the selected item is displayed. All that is working correctly.

The problem is, when a different dropdown list is selected, the previously displayed value is hidden.

My question: How do I get the previously selected item (layer) to remain on the slide? I have set the item to remain until the slide ends but that doesn't seem to be working.

Any suggestions on how I can get each of the selected items from the dropdown lists to remain on the slide for the duration of that slide?

Thanks.

Michael