This document is a Sidebar Item. You can use Containers, Documents, Widgets and Calendars as Sidebar Items. 

Look at the Keywords Field of any object in the Sidebar: if you write a filename there, the Sidebar object will only be visible on pages with that exact filename. You can add more pages by comma-separating a keyword for each. 

This is context-sensitivity in FirstMagic: use the Keywords to attach both Footer and Sidebar objects to any particular page or set of pages.