private void btn_createTest_Click(object sender, RoutedEventArgs e)
{
this.Hide();
NewTest newTest = new NewTest(user);
newTest.ShowDialog();
newTest = null;
this.Show();
}
private void btn_ok_Click(object sender, RoutedEventArgs e)
{
Test test = (Test)cbo_tests.SelectedItem;
this.Hide();
NewTest newTest = new NewTest(user, test);
newTest.ShowDialog();
newTest = null;
this.Close();
}