CMS moving left and up

class Window_Base < Window

def initialize(x, y, width, height)
    super()
    @windowskin_name = $game_system.windowskin_name
    self.windowskin = RPG::Cache.windowskin(@windowskin_name)
    self.x = x
    self.y = y
    self.width = width
    self.height = height
    self.z = 100
    @dest_x = self.x
    @dest_y = self.y
    end

    def start(dest_x, dest_y)
        @dest_x = dest_x
        @dest_y = dest_y
    end

    alias cms_update update
    def update
    super
    # Reset if windowskin was changed
    if $game_system.windowskin_name != @windowskin_name
      @windowskin_name = $game_system.windowskin_name
      self.windowskin = RPG::Cache.windowskin(@windowskin_name)
    end
        if self.x < @dest_x
            self.x += 32
        end
        if self.x > @dest_x
            self.x -= 32
        end
        if self.y < @dest_y
            self.y += 32
        end
        if self.y > @dest_y
            self.y -= 32
        end
    end
end