private static void AnimateWidth(FrameworkElement element, double from, double to)
{
var storyboard = new Storyboard();
var fade = new DoubleAnimation
{
From = from,
To = to,
Duration = TimeSpan.FromSeconds(1)
};
Storyboard.SetTarget(fade, element);
Storyboard.SetTargetProperty(fade, new PropertyPath(WidthProperty));
storyboard.Children.Add(fade);
storyboard.Begin();
}