public void WhenOpenDialogsAreOpenIsExist()
        {
            object id = Guid.NewGuid();

            _dialogHost.Identifier = id;
            bool isExist = false;

            _ = _dialogHost.ShowDialog("Content", new DialogOpenedEventHandler((sender, arg) =>
            {
                isExist = DialogHost.IsExistDialog(id);
            }));
            Assert.True(isExist);
            DialogHost.CloseDialogCommand.Execute(null, _dialogHost);
            Assert.False(DialogHost.IsExistDialog(id));
        }