Deleting Collections vs. Deleting Collection and Items
If you no longer need a collection (folder) for any reason, you can delete it from My Library by right-clicking on the folder and selecting either Delete Collection or Delete Collection and Items. When you Delete Collection, the individual items within that collection will remain in your My Library folder and any other folders which contain those items. However, if you Delete Collection and Items, the individual items will be deleted from all of the folders containing the items. Did you accidentally delete items? They can still be retrieved from your Trash.
Organizing with Tags from McGill U. Library
Organizing with Collections from McGill U. Library