As we all saw that Google launched its own Social Networking (Google +) site with lots of new and competitive features to Facebook and its going to be problem for Mark Zuckerberg. So Facebook also started rolling new features like Video Chat and Group chat and now this week a new one as Sidebar.
Sidebar is introduced in the chat option and concept of list is not there. You can easily notice when you able your chat. There are some new options which are added like as Available to Chat, Hide Sidebar, Chat Sounds and Limit Availability.
You can check or uncheck the option Available to Chat to make yourself online or offline and even the sidebar can be hidden as it opens up when clicked. So if want it to be minimized you have to choose hide sidebar.
Previously there was only option to limit yourself or make you offline to specific people by clicking on the list but now a new option Limit Availability is added so as to make you offline to specific ones.
All these features are rolled out sudden as Google is making competition stiffer with their advaned features so they are not so perfect as if users who are online exceeds then it goes beyond the browser area and its not possible to scroll up. So it may be soon fixed.