I wanted to view all the different chat windows and the buddy list side by side in a single window. There is no such feature in stock Pidgin installation. Fortunately I found a plugin for same from this ticket.
You can find the build / install instructions on the wiki, however here is how you can do it on Ubuntu 14.04 and other OSes.
First install Pidgin development headers
sudo apt-get install pidgin-dev
Now build the plugin
git clone https://github.com/dm0-/window_merge.git cd window_merge mkdir m4 autoreconf -fi ./configure make install plugindir=~/.purple/plugins
Once it is installed, you have to enable it from
Tools -> Plugins, then enable «Window Merge». Here is a preview of window merge in action: