Session Links
When in play mode, an extra row of buttons appears at the top of the Campaign Builder. These buttons are used to navigate to various parts of the Current Session.
Clicking the "To-Do" button will open the To-do list for the Current Session's campaign.
Clicking any other button will switch to the corresponding tab in the Current Session, regardless of what you have open in the Campaign Builder.
In both cases, if the Session/Campaign is already open, it will use the existing tab rather than creating a new one.