INamingContainer has been removed from the Container controls (Window, Panel, etc), so you no longer need to call .FindControl() when trying to access nested web controls.

Controls can now be referenced directly by their Server-Side or Client-Side ID.

Example

<cool:Window
    runat="server" 
    ID="Window1">
    <Content>
        <cool:Calendar ID="Calendar1" runat="server" />
    </Content>
</cool:Window>

<script runat="server">
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!IsPostBack)
        {
            this.Calendar1.SelectedDate = DateTime.Today.AddDays(1);
        }
    }
</script>

New code <STRIKE>will be available with Version 0.4</STRIKE> is available with version 0.3.1.