When the mouse is moved or its buttons are pressed, the system generates
input events that represent the actions.  The input events are taken from
the input chain by Intuition when the active window requires the events.
Note that only input for a specific window will be affected by changes in
that window's IDCMP flags.

Most events generated by the user with the mouse are used by Intuition.

As the user moves the mouse, Intuition changes the position of its
pointer.  The Intuition pointer moves around the entire video display,
mimicking the user's movement of the mouse.  The user points at an object
by positioning the hot spot of the pointer over the object.  The hot spot
is the active part of the pointer image; the hot spot for Intuition's
default pointer is the pixel at the tip of the arrow.

After pointing to an object, the user can perform some action on that
object by selecting it with one of the mouse buttons.  These can include
any of the actions specified above, such as dragging or double clicking.

The left mouse button is generally used for selection, while the right
mouse button is most often used for information transfer.  The terms
selection and information are intentionally left open to some
interpretation, as it is impossible to imagine all the possible uses for
the mouse buttons.

The selection/information paradigm can be crafted to cover most
interaction between the user and an application.  When using the mouse,
the application should emphasize this model.  It will help the user to
understand and remember the mouse control of the application.

Applications that handle mouse button events directly, bypassing the menu
and gadget systems, should use the same selection/information model used
by Intuition.

 select button    menu button