In the same way as a model keyboard is used to describe the program independent of various keyboards a virtual button convention is used to describe the behaviour of the program independently of the number of buttons on the mouse. This manual assumes a three-button mouse with the buttons being defined from left to right as BSelect, BTransfer and BMenu. By convention, BSelect is used to select objects, BTransfer is used for drag-and-drop operations and BMenu is used to bring up pop-up menus. Perhaps the most common variation in the assignment of mouse buttons is the reversal of the order for left-handed users.
I shall often refer to mouse operations without specifying a particular button in this guide. Whenever I do this you can safely assume that you should use BSelect.