When I select files from (all items) to add to a specific collection on the app, the selection can’t be added. But when I do that from the web, it appears in my app.
Correct, I use the button and select the file then select the (folder +) icon, it shows the collections, but it won’t let me to select any of the collections in order to select the add button.
The dragging is working, but I don’t usually use it.
You can drag items to collections or use the button to do so. What exactly are you trying, and what isn't working?
The dragging is working, but I don’t usually use it.