The settings of each overview window are stored in the project file. Thus the overview window is displayed automatically when the project and the corresponding view is opened. Once an overview window has been defined, it can only be deleted with the command Overview Remove. If a view is deleted, the corresponding overview window is deleted too.
Visualization of the visible extent: The extent currently visible in the view will be displayed in the overview as a yellow cross-hatched rectangle with broad yellow borders. The width of the hatch is adapted to the size of the extent(the visibility of the themes is therefore not diminished by the lines of a narrow hatch at large extents). If this rectangle is becoming too small, the position will be visualized as a yellow crosshair. If the extent displayed in the overview is too small, it can happen that the rectangle can't be entirely displayed or the whole overview will be covered by a yellow hatch.
Zoom Mode: Normally the overview window is set to the zoom mode, i.e. you can select an extent by draging a rectangle in the overview with the mouse - the view is zoomed to the selected extent. If the chosen extent doesn't comply with the form factor of the view (relation between width and height), a larger extent is displayed in the view. Selecting an extent is further limited to the size of the panning zones (the size or the scale of these zones can be defined in the dialog at Panning Options). By default the overview is divided in 20x20 zones. If the width or height of these zones is defined too large (i.e. the overview is divided into very few zones) the selection in the zoom mode is affected.
Pan Mode: If you click in the overview window with the mousewhile pressing the Ctrl key, you can switch from zoom to pan mode. The color of the visible extent changes from yellow to turquoise and the focus for keyboard input stays in the overview window (the title bar of the window stays colored - not gray). Now you can navigate in the overview with the keyboard, i.e. you can move the visible extent of the view with the cursor keys
To stop the pan mode and switch back to the normal zoom mode, just put the focus from the overview window to any other window (just click with the mouse at any point of the ArcView window outside of the overview window).
Visibility: Normally the overview window shall only be visible when the corresponding view is visible (default setting). If you have several overview windows with permanent visiblity, you can use them to open or activate the corresponding views (just click on an overview to open its view or bring it to the front of all other open documents).
Change window size and position: You can adjust the size of the overview window with the mouse as you like. After changing the window size, the overview will be updated automatically (this may take a few seconds). The window can also be moved to any position on the windows desktop with the mouse - even beyond the ArcView window or to a second display.
Fixate window size and position: After creating the overview window, it has a frame and a title bar which enables you to resize or move it with the mouse. Just click anywhere in the overview window with the mouse while pressing the Ctrl key, and the frame and the title bar are hidden. Thus the window needs less space on the screen and it can't be resized or moved any more. Click in the window while pressing the Ctrl key again to reactivate its frame and title bar.
Speed of refreshing the overview: It is recommended to keep overview windows small and display simple themes. Otherwise the time spent on refreshing the overview increases. Themes with plenty and small structures shouldn't be displayed in the overview, because they increase refresh time a lot, but aren't helpful in the overview.
Problems displaying themes: If point themes are used, the point size is scaled down to a third and reduced to maximal 5 pt. Graphic elements that are attached to a theme (ArcView command Attach Graphics) won't be displayed in the overview. The usage of annotation themes is not recommended. As the overview is exported to an image file, all polygon themes using transparent raster fills won't be displayed transparent but opaque/white (same problem as printing in ArcView) - use vector fills instead. Legends based on a joined field (ArcView command Table - Join) can't be displayed, because all joins will get lost in the overview.
Updating themes and legends: When the data source of a theme has been deleted or destroyed, it will automatically be removed from the overview when opening the project. If you want to add or remove themes, open the customize dialog with the function Overview Open while pressing the Shift key and select the desired themes. If you have modified legends of themes, that are already displayed in the overview, open the customize dialog, activate the Update option and click on 
. The overview window will then be rebuilt with the new legends. If you want to display a theme in the overview with a different legend as in the view, you must add this theme to the view, load the desired legend and create the overview window (you can delete this theme from the view afterwards). If you rebuild the overview using the Update option, this legend will be updated and lost though.