Fluent Syntax - generic methods

public abstract class Control { }

public sealed class Image : Control {
    public Image WithUrl(string url) { Url = url; return this; }
    public Image WithZoomFactor(float zoomFactor) { ZoomFactor = zoomFactor; return this; }
}

public sealed class Label : Control {
    public Label WithText(string text) { Text = text; return this; }
}

public class StackPanel: Control {
    public void AddChild(Control control) { }
}

public class Canvas: Control {
    public void AddChild(Control control, Point point) { }
}

new Image()
    .WithZoomFactor(0.75f)
    .PlacedIn(canvas1).At(0, 0)
    .WithUrl("flower2.jpg");

new Image()
    .WithZoomFactor(0.75f)
    .PlacedIn(stackPanel2)
    .WithUrl("flower1.jpg");

new Label()
    .WithText("Dandelion (lat. Taraxacum officinale)")
    .PlacedIn(canvas2).At(50, 200);

// This should not compile - PlaceIn() is in canvas and is not followed by .At()..
// new Image().PlacedIn(canvas2).WithUrl("flower2.jpg");

public static T PlacedIn<T>(this T control, StackPanel stackPanel) where T : Control {
    return control;
}