You can reset the warning by quitting Agenda and entering the following in the Terminal.app:
defaults delete ~/Library/Containers/com.momenta.agenda.macos/Data/Library/Preferences/com.momenta.agenda.macos suppressDeleteSectionsAlert
You can reset the warning by quitting Agenda and entering the following in the Terminal.app:
defaults delete ~/Library/Containers/com.momenta.agenda.macos/Data/Library/Preferences/com.momenta.agenda.macos suppressDeleteSectionsAlert