def erase
      children.each { |c|
        c.erase
      }

      @win.werase if @win

      component.component.erase if cdk? && component? && component.init?
    end
def erase
      children.each { |c|
        c.erase
      }

      @win.werase if @win

      component.component.erase if cdk? && component? && component.init?
    end
Erase window drawing area