For multi-screen implementations other than Xinerama, such as Single Logical Screen, it is possible to simulate a Xinerama configuration if the total screen seen by fvwm is made up of equal sized monitors in a rectangular grid. The XineramaSls command turns SLS support on or off or toggles it to the opposite state, depending on if the boolean argument is "True", "False" or "toggle". If no argument is given, this is treated like "toggle". The default layout uses one by one screens. To configure the layout, use the XineramaSlsSize or XineramaSlsScreens command.