unless background.nil?
          background_attribute = ::LibUI.new_background_attribute(@background[:r].to_f / 255.0, @background[:g].to_f / 255.0, @background[:b].to_f / 255.0, @background[:a] || 1.0)
          ::LibUI.attributed_string_set_attribute(@parent_proxy.attributed_string, background_attribute, @start, @start + @string.size)