TabContainer/TabPanel set focus to control on load and in postback

I am using the Tabcontainer/Tab Panel for my ASP.NET application.  On page load, I am setting the ActiveTabIndex to the first tab:

protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                LoadFormGrid();
                TabContainer1.ActiveTabIndex = 0;
            }
        }

I would when the tab displays, I would like to set the focus to a textbox control on the tab panel.

How can I do this?  (I have tried various things posted on the web to no avail)

I also have an event (drop down list selected index changed) in which I would like to set the focus to a specific control on the tab panel.  How can I do this?

Thank you,

Becky McDermott