The Mouse Motion Command Interpreter (MCI) is easy to master and is one of the most powerful features of ARRIS. It allows you to execute a command by simply pressing the right button of your mouse and dragging the cursor.
To illustrate this feature,
we will discuss how to execute the Zoom Window command using MCI.
To begin, move the cross hair on the screen to the lower left corner of an
area you wish to enlarge. Press the right button of the mouse and while holding
it down drag the cursor
up and to the right (Figure 1). When you get to the upper right corner of the
area you want to enlarge, release the right button of the mouse. The view
will change, zooming in to the area where
you moved the mouse. Notice that while you moved the mouse across the screen,
the cursor left a trail of white dots (Figure 2). This is a visual reference
that helps you follow the mouse movement without
looking away from the screen. 
Now try the opposite motion. Press and hold the right mouse button down and drag
the mouse down and to the left. Release the right mouse button. This executes the Last Window command, which will restore the view on the screen
to the previous view. You have now mastered the concept of mouse motion. 
For the most basic commands that are executed hundreds of times a day, Mouse MCI is an essential tool. The more you use it, the faster it will become, and the more intuitive it will be. It is one of the features of ARRIS that Power Users say they can't live without!