How do I show current users in a channel in a panel on the right in irssi

How do I show current users in a channel in a panel on the right in irssi?

I have tried googling for this but could not find anything. The screenshot here: http://ift.tt/1GgiUJw shows what I am referring to.

I did think it was part of the theme logic but upon activating a theme it has only changed the colours.

I am new to irssi and would appreciate the xchat-like interface of showing the users without the need to type /names .

Thanks!