lectedNode: {
        value: "",
        reflect: true
      },
      /*
        @property {Object} markedNode
        @description Marked tree node reference
      */
      markedNode: {
        value: "",
        reflect: true
      },
      /*
        @property {Object} drag
        @description
      */
      drag: {
        value: false,
        reflect: true
      }
    },
    privateProperties: {
      /*
        @property (private) {Object} _refs 
        @description Quick access to the tree struct