Inconsistencies in ASP.NET dealing with dynamically changing control tree

Hi there,
Been trying to puzzle this one out, but ASP.NET appeas to be behaving inconsistently. I've been experimenting with adding controls dynamically into a page. I have two user controls.
UserControl.ascx looks like this
<%@ Control Language="C#" AutoEventWireup="true" CodeFile="UserControl.ascx.cs" Inherits="Test" %> <h1>test control</h1> <asp:BulletedList ID="BulletedList1" runat="server"> <asp:ListItem>can</asp:ListItem> <asp:ListItem>you</asp:ListItem> <asp:ListItem>see</ ...