# File lib/apotomo/widget/tree_node.rb, line 11
    def setup_tree_node(parent) # DISCUSS: make private?
      @parent       = nil
      @childrenHash = {}
      @children     = [] # TODO: order of widgets in this variable isn't tested anywhere!!!
      
      # DISCUSS: and what if not a Widget?
      parent.add_widget(self) if parent.kind_of? Widget # TODO: as long as cells needs parent_controller.
    end