[whpalmer4]

When you complete an action, OmniFocus no longer shows it to you, but it is not erased. The usual views simply don't show completed actions. Go to the Perspectives menu and choose the Completed perspective if you wish to see completed items, or the All Items perspective will show you everything whether completed or not. Only if you actually delete the action is it removed from the database. After enough time spent using OmniFocus, it will eventually propose to move older completed items to an archive database, which removes them from the active database, but they are still easily accessed as long as you are on the machine with the archive.