# File ../lib/fox/core.rb, line 228
    def +(other)
      if other.kind_of?(FXRectangle)
        xx = [other.x, self.x].min
        ww = [other.x+other.w, self.x+self.w].max - xx
        yy = [other.y, self.y].min
        hh = [other.y+other.h, self.y+self.h].max - yy
        FXRectangle.new(xx, yy, ww, hh)
      else
        raise TypeError, 'expected FXRectangle'
      end
    end