You can make any new folder button open in a popup when you are creating it. Just toggle Open in Popup ON before you tap Done.

You can also edit an existing folder button to make it open in a popup. Opening in popup is a property of the button that opens the folder, not the folder itself. This means that you will select and edit the button that opens the folder when tapped. 

1. Go inside the folder where you see the folder button you want to make open a popup.
2. Tap the Edit button in the bottom toolbar to open Edit Mode.
3. Tap the folder button to select it.

4. In the Basics section of Edit Mode, select the Actions row. 
5. Tap the existing Open Folder action row.
6. Scroll down the list of actions to the Open Folder row. Tap More Info on the right side.
7. Toggle Open in Popup ON.
8. Tap Done to close Edit Mode.

Suggested articles

• Make a new folder
• Change a folder’s grid size