Vista - Help with Custom Control

I'm looking for some help with a custom control.

I have a control that I'm trying to create the control is composed of two
borders one on top of another, the bottom border background is a solid color
and the top border background is a linear gradient with a blur effect. I am
trying to create a dependency property so I can change the background color
of both borders at once. The problem is borders are not changing when I set
the property. Here is a simpler version of the code, basically when the set
method gets called I want the front border to be set to blue. Is there a
refresh I need to call or something?

public partial class UserControl1
{
public static DependencyProperty dpTabColor;

static UserControl1()
{
dpTabColor =
DependencyProperty.Register("TabColor",typeof(Brush),typeof(UserControl1));
}

public UserControl1()
{
this.InitializeComponent();
}

public Brush TabColor
{
get { return (Brush)base.GetValue(dpTabColor); }

set
{
base.SetValue(dpTabColor, value);
SolidColorBrush myBrush = new SolidColorBrush(Colors.Blue);
this.FrontBorder.Background = myBrush;
}
}

}