maximize_over_multiple_monitor.lua

        function (c)
            c.floating = true
            local geo = {}
            geo.x = screen[1].geometry.x
            geo.y = screen[1].geometry.y
            geo.width = screen[1].geometry.width
            geo.height = screen[1].geometry.height
            geo.x2 = geo.x + geo.width
            geo.y2 = geo.y + geo.height
            for s in screen do
                local geo2 = s.geometry
                geo.x = math.min(geo.x, geo2.x)
                geo.y = math.min(geo.y, geo2.y)
                geo.x2 = math.max(geo.x2, geo2.x + geo2.width)
                geo.y2 = math.max(geo.y2, geo2.y + geo2.height)
            end
            c:geometry{
                x = geo.x,
                y = geo.y,
                width = geo.x2 - geo.x,
                height = geo.y2 - geo.y
            }