Note that you can shift-click in the list if you want to trash several (or all) events. Alt gr can also be used to select several events.
Click the Trash button, or press the Delete (Del) key, to trash the selected event(s).
You are strongly advised to keep the warning messages in Preferences enabled (ticked) to avoid that events are accidentally trashed.
Trashed events will be put in Windows Recycle Bin, from where you can rescue them. You can put an accidentally trashed event folder back to its original place in C:\Duplimate\BOS\Events to make it (re)appear in BOSís list of events.
Click the Archive button to archive the selected event(s).
Archived events (ctrl+A) can be retrieved and reinstated in the event list at any time. Archive should therefore be your normal choice when the list of events needs to be shortened.