The Overview extension adds two new choices to the View menu of selected 
View DocGUIs. These choices allow you to create and control an overview views.
The Overview view is a small view that displays the full extent of the current
view and a rectangle outlining its extent. When you change the display extent 
of the current view, the graphic on the overview view changes with it. If you 
select the overview view, you can modify the rectangle to change the display 
extent of the current view.

Whenever you close a view with an associated overview, the overview closes. 
When you open a view with an associated overview, the overview opens. If your
overview gets closed or lost among many other documents, you can restore it to
the top by using the Display Overview choice in the View DocGUI's View menu.

The overview view has a much simplified user interface. It provides controls
to change the extent rectangle and also to delete unwanted themes from the view.

Requires: This requires at least one View DocGUI with a menu named View.