private void btn_Quit_MouseLeave(object sender, MouseEventArgs e) { DoubleAnimation btnHAnimation = new DoubleAnimation(); btnHAnimation.Duration = new Duration(TimeSpan.FromSeconds(0.7)); btnHAnimation.To = 35; DoubleAnimation btnWAnimation = new DoubleAnimation(); btnWAnimation.Duration = new Duration(TimeSpan.FromSeconds(0.7)); btnWAnimation.To = 35; Quit.BeginAnimation(Button.HeightProperty, btnHAnimation); Quit.BeginAnimation(Button.WidthProperty, btnHAnimation); }