Left mouse button: Used to pull down menus in the menu bar (as for File, Plan, Options and Help menus in the main window above) and to select regions in the various plan windows. Be careful when you use the button to bring different windows to the front. Always click on the border or title bar. Clicking within the window may trigger unanticipated actions within the code.
Middle mouse button (Unix only): Not used.
Right mouse button: Used to trigger the pop up menus that control various options within the windows. The pop up menus may be different in different parts of the window. There is no visual indication when a pop up menu is available until you press the right hand button. Pressing the right button when there is no pop up menu will have no effect on any other part of the program.