This function is powerful. One mouse click can update many notes at once. Changes made here are not easily reverted.
Use this mass update function only after you have selected which notes you want the update to apply to.
For example, if you are un-assigning notes for a certain user or deleting notes for a certain book, use the Select screen first to make sure that only the notes for that user or book are selected.
Amount of notes to be updated in one go: 0