The Opening Filter isolates the Openings that will be available to 'Find' using the Find Opening button and Report on under any of the Reporting Menus.
Example:
If I set an Opening Filter for Licence = A12345 and Surveys Planned in 2023. Let's say the number of openings that meet that Filter is 55.
When I go to the All Activities, at the top it shows the (filter name -55 Openings). The All Activities page will show ALL Activities for the 55 Openings that meet the Filter including Surveys, Planting, Brushing, etc...planned and completed.
To only see the Planned Surveys for 2023, set those filters on the All Activities page.