public function force_open() {
        $this->forceopen = true;
        if ($this->parent !== null) {
            $this->parent->force_open();
        }
    }
public function force_open() {
        $this->forceopen = true;
        if ($this->parent !== null) {
            $this->parent->force_open();
        }
    }
public function force_open ( ) { $ this -> forceopen = true ; if ( $ this -> parent !== null ) { $ this -> parent -> force_open ( ) ; } }
Forces this node to be open and at the same time forces open all
parents until the root node.

Recursive.
Forces this node to be open and at the same time forces open all parents until the root node .