Whenever you have selected a Collection in the left pane of the Library, the center pane displays its contents. When you select by clicking or using the Select: All option, the Actions dropdown is what enables you to take certain actions on the nested Collections and Galleries within.
Add gallery to another collection
Use this action to copy the entire gallery and all of its contents into another Collection. Edits to a copied Gallery effect both the original and the copy. This feature is not frequently used because a copy of a file is much more flexible.
Move to another collection
Moves the Collection or Gallery out of the current Collection and into another.
Edit visibility & inheritance
Batch edit the permissions applied to nested Collections and nested Galleries.
Be mindful of the native permission before you edit in batch. If you have permissions already applied to the Collections or Galleries you are editing, you will be prompted to override when inheriting.
Enable/disable Watermark
If you have selected one or more Galleries in the center pane, you can enable or disable their watermark settings in batch.
Delete
You can delete a Collection or Gallery from the Library by clicking this action. You will be prompted to confirm the delete and notified if you are also deleting any files. If any of the Galleries you are deleting contain virtual copies of files, you will delete the files from all locations across the library. See Remove from Gallery for more information.