If there are too many chat windows that overlap on your desktop, you can merge them into a single chat window with tabs.

Open system settings from BigAnt main panel

1. Go to the tab Chat Windows
2. Select Tabbed chat windows and click Ok button to apply your setting
   
3. Thus all BigAnt chat windows will be listed in a frame, and you can switch the conversation by clicking contact at left side bar, the tab glows when you click and chat with him/her