The application button is the large round button found at the top left of the ribbon
control. With Office 2010 styling this appears as a ribbon tab and with Office 2007
styling it is a round orb. Pressing the button causes a drop down menu to appear
that has three elements.
Here you can see the application button menu has a context menu on the left side,
a recent documents list on the right side and additional buttons at the bottom edge.
You can remove the recent documents area from display if it is not relevant to
your application. You can even remove the application button entirely from the
ribbon if that is required.