This page shows how to build a skin with an additional icon. Here we use it to show a help window which is based on the window content (context sensitive).
See the skin definition (skins/default-plus/wm-window.html) for the source code. To add a print icon instead of a help icon, please have a look at the Forum Print Issue.

By the way this is a WinLIKE skin hack by Micheal Andrews from www.nofearsoftware.com.