def finalize!
      erase
      @@registry.delete(self)

      children.each { |c|
        del_child c
      }

      cdk_scr.destroy if cdk?
      component.finalize! if component?
    end
def finalize!
      erase
      @@registry.delete(self)

      children.each { |c|
        del_child c
      }

      cdk_scr.destroy if cdk?
      component.finalize! if component?
    end
Invoke window finalization routine by destroying it
 and all children