After you select the Delete selected field menu from the Field List Area context menu, you will see this dialog box:
Confirm that you want to delete the selected field.
As soon as you press OK, a new change log entry will be created. The field will only be deleted when you explicitly request to save the active changes in the change log. You therefore has the ability to regret this action at any time.
If you have selected multiple documents, you change will be processed on all selected documents.