public void NullLocalValue () { Brush blue = new SolidColorBrush(Colors.Blue); Brush red = new SolidColorBrush(Colors.Red); Style style = new Style(typeof(Canvas)); style.Setters.Add(new Setter(Canvas.BackgroundProperty, red)); Canvas c = new Canvas(); c.Background = blue; c.Style = style; Assert.AreEqual(blue, c.Background, "#1"); c.Background = null; Assert.AreEqual(null, c.Background, "#2"); c.ClearValue(Canvas.BackgroundProperty); Assert.AreEqual(red, c.Background, "#3"); }