protected override void OnClosed(EventArgs e)
        {
            base.OnClosed(e);
            ParticleConstraintDialogueVM vm = DataContext as ParticleConstraintDialogueVM;

            vm.Close();
        }
        void SetupDataContext()
        {
            ParticleConstraintDialogueVM vm = new ParticleConstraintDialogueVM();

            DataContext = vm;
            if (vm.CloseAction == null)
            {
                vm.CloseAction = new Action(Close);
            }
        }