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: 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!