IDL supports the use of mice with up to three buttons. Because some systems use mice with one or two buttons, IDL provides mechanisms for simulating a three-button mouse.
Many mice used with Microsoft Windows systems have only two buttons. To simulate a middle-button press, hold down the Control key and press the left mouse button.
Many mice used with Macintosh systems have only one button. The X Window System software provided with MacOS X provides multi-button mouse emulation, allowing you to configure the system to generate middle- and right-button press events. See your MacOS X system documentation for details.