I use a Kensington Orbit with MouseWorks 5.02 attached to the ADB of a LC475 running Mac OS 8.1. I use the left button as a standard mouse click, the right button as a control-click and both buttons clicked together as a click-lock. Application specific setting are possible. For example, in HyperCard I use the right button to open the script of a selected button or field. Similar behaviour can be obtained with a Microspeed MacTRAC, using the appropriate control panel (MacTRAC 3.4).