public function persistentFreeze($persistent = null)
    {
        $old = $this->persistent;
        if (null !== $persistent) {
            $this->persistent = (bool)$persistent;
        }
        return $old;
    }
public function persistentFreeze($persistent = null)
    {
        $old = $this->persistent;
        if (null !== $persistent) {
            $this->persistent = (bool)$persistent;
        }
        return $old;
    }
public function persistentFreeze ( $ persistent = null ) { $ old = $ this -> persistent ; if ( null !== $ persistent ) { $ this -> persistent = ( bool ) $ persistent ; } return $ old ; }
Changes the element's persistent freeze behaviour

If persistent freeze is on, the element's value will be kept (and
submitted) in a hidden field when the element is frozen.

@param    bool    New value for "persistent freeze". If omitted, the
method will not set anything, just return the current
value of the flag.
@return   bool    Old value of "persistent freeze" flag
Changes the element s persistent freeze behaviour