For Windows – Keep Pidgin’s buddy list “always on top” of other windows for easy access to instant messaging without the hassle of switching windows. First, head to Tools → Plugins in the buddy list.

Scroll to the bottom, make sure Windows Pidgin Options is checked, then click it and Configure Plugin.

Next to Keep Buddy List window on top, click the menu and select Always. Hit Close to both windows and Pidgin should now remain on top of your other windows.

The "Transparency" plugin is capable of making your conversation windows stay on top. Both plugins are included with Pidgin

f you just want the buddy list to remain above other windows, you can dock it to the side of your desktop using the "Windows Pidgin Options" plugin and set the "Always On Top" option accordingly. The "Transparency" plugin is capable of making your conversation windows stay on top. Both plugins are included with Pidgin.

A user has also recommended a freeware Windows utility called ​PowerMenu, which can set any window to be 'Always On Top' and may provide additional flexibility.