Drop down value being reset

Hi,
I have a strange problem.
I have two usercontrols.In one I am either
typing a program name or selecting from
a existing list and putting it in session.
Then in the other usercontrol I am checking
whether the session values exists or not and then setting the selected
value of another dropdown according to the program name
selected in the first one.
My code for setting the value in the second one is as
below:
protected void Page_Load(object sender, EventArgs e)
    {

        FillProgramList(select);
        if (Session["ProgramName"] != null)
        {
            //FillProgramList(select);
            programToExecute = Convert.ToString(Sess ...