The season treeview lists the season for each property. By default it will show only the current season. Tick the Closed Season option at the bottom of the treeview to display all seasons.
Click on a season to view all activities that occurred for the season irrespective of location. With a season highlighted, you can swap back to the Location treeview and everywhere that season occurred will be ticked as a reference.
You can perform an activity for a current season from the season treeview. Highlight the season and perform an activity. The activity will be recorded against every location for that season.