If you try to run a test like the following from NUnit, you will find that it does not work.
You get an InvalidOperationException telling you that “The calling thread must be STA, because many UI components require this”.

http://www.hedgate.net/articles/2007/01/08/instantiating-a-wpf-control-from-an-nunit-test/

System.InvalidOperationException: Beim aufrufenden Thread muss es sich um einen STA-Thread handeln, da dies für viele Komponenten der Benutzeroberfläche erforderlich ist.

Changing the Selected Item's Backcolor in a ListBox

if ((e.State & DrawItemState.Selected) == DrawItemState.Selected)
     e = new DrawItemEventArgs(e.Graphics, e.Font, e.Bounds, e.Index, 
     e.State ^ DrawItemState.Selected, e.ForeColor, Color.Red);

http://www.codeguru.com/csharp/csharp/cs_controls/custom/article.php/c13423/#more

Custom Properties on a Control with Serialization and Reset:

public class MyLabel : Label
    {
        public MyLabel()
        {


        }


        private static readonly string txtExtendedDefaultValue = "Extended Text Property";
        private string txtExtended = txtExtendedDefaultValue;
        public string TxtExtended
        {
            get { return txtExtended; }
            set { txtExtended = value; }
        }


        void ResetTxtExtended()
        {
            txtExtended = txtExtendedDefaultValue;
        }


        bool ShouldSerializeTxtExtended()
        {
            return txtExtended != txtExtendedDefaultValue;
        }


        private string txtSimple = "Simple Text Property";
        [DefaultValue("Simple Text Property")]
        public string TxtSimple
        {
            get { return txtSimple; }
            set { txtSimple = value; }
        }
    }

With the use of the SetWindowLong API, you are aligning each object as you want. Add these methods' associated properties.

http://www.codeguru.com/csharp/csharp/cs_controls/custom/article.php/c15261__6/