Completable events
CalenGoo has a function that allows you to mark events as “Completed”. To use it you have to turn it on under “Settings > Display and Use > General > Completable events”. Using "All events are completable" you can decide if all events should get a checkbox or only some. You can also limit this function to some calendars. And you can specify how completed events should be displayed:
Afterward your events will have a checkbox in the detail and edit view to mark them as completed. And depending on your configuration the completed events will be displayed in a special way:
Floating events
In addition to using completable events you can also enable “Settings > Display and Use > General > Floating events” to use floating events. Floating events are events that are moved from the past to the current day until they are marked as completed. Then they will stay on that day. Future floating events are not modified.To make an event floating just check the “Floating” checkbox in the edit view of the event. This “Floating” checkbox is only visible if “Floating events” has been turned on as described above.
It is also possible to mark an event as floating in Google Calendar. Just add “[F]” to its title. When CalenGoo syncs that event, it will automatically recognize it as floating.