protected override void RemoveItselfFromDependancies()
 {
     _packProperties.RemoveDependancy(this);
     _palletProperties.RemoveDependancy(this);
     if (null != _interlayerProperties)
     {
         _interlayerProperties.RemoveDependancy(this);
     }
     // base
     base.RemoveItselfFromDependancies();
 }