[Pan] command performs panning of the active view by mouse dragging with left button down.
One dragging, that is, the mouse movement from the instance of mouse button down
to the instance of mouse button release is the command operation and the
commnad is terminated when the mouse button is released. After the command is
invoked, the pressing of left button down changes the mouse cursor to .
Dragging with the cursor shape, Pan is applied and users are able to
real-timely confirm how the panning is done.
Another dynamic way of view-panning other than this command is: