def create_child(h={})
      c = self.class.new h.merge(:parent => self)
      c.colors = @colors if colored?
      children << c
      c
    end
def create_child(h={})
      c = self.class.new h.merge(:parent => self)
      c.colors = @colors if colored?
      children << c
      c
    end
Create child window, this method should not be invoked
 by end-user, rather it is is invoked the Layout#add_child
 is called.