Overview Window

The Red View Box represents the size and position of your current view area.  Drag the box with your left mouse button to change your view position within the larger MI/X window.

X client windows are represented by window thumbnails.  You can drag individual client windows by holding down the Shift key and dragging with the left mouse button.   You can double-click on a client thumbnail to have the view box re-center over that client window.

You can control the initial open/closed state of the Overview window on the Screen tab of the Preferences dialog.