Based on customer feedback, we've added a setting for the web meeting client, to indicate whether meetings open in the current window or in a new window or tab. This capability makes it easier for people to get back to the meeting center if they need to jump from one meeting room to another.
This behavior is controlled at the server level, with this setting:
meetingroomcenter.openRoomInNewWindow (default: true)
Sametime 8.5.2 Features: Open meeting rooms in new windows or tabs