I was at a table and played a long session against a certain player. I couldn't remember which table it was so I created a filter for exactly 2 players.
I was expecting to see in the session list only those sessions that contained hands matching my filter but to my surprise, it showed all sessions played that day. Also, the number of hands column contained the total number of hands played at the table rather than the number of hands matching the filter.
The only thing the filter did do is filter the hands in the Session Hands list. I could find my session by clicking on each session and looking at the Session Hands report and see where I played these hands.
PT2 also behaves the same way. Not sure what other filters behave this way.