ATLAS Issue: RegisterStartupScript and RegisterClientScriptBlock do not work in atlas:UpdatePanel?

To understand this ATLAS issue imagine there is a page which has an asp:button control and corresponding handler, which is called when the button is clicked. The requirement is to show the alert window, when the button ‘cmd’ is clicked.  To do that the handler function ‘cmd_Click’ register the client script block by calling of RegisterStartupScript (the same issue can be noticed by using of RegisterClientScriptBlock too). This pattern is mostly when som pop-up windows have to be opened.

<asp:Button ID="cmd " runat="server" OnClick="cmd_Click" />

protected void cmd_Click(object sender, EventArgs e)

{

       string script = @"<script language=""javascript"">

                    alert(‘hello’)</script>";

       if (IsPostBack){

       this.ClientScript.RegisterStartupScript(this.GetType(),

       "ShowPopup", script);     

       }

  }

}

If the same ASP.NET code is inserted in the atlas:UpdatePannel control the alert-window will not appear.

<atlas:UpdatePanel ID="UpdatePanel1" runat="server" Mode="Always">

 <ContentTemplate>

  <asp:Button ID="cmd " runat="server" OnClick="cmd_Click" />

 </ContentTemplate>

</atlas:UpdatePanel>

The generated script code should usually appear at the buttom of the HTMP page:

<script language="javascript">

alert("2");

</script>

However the generated script looks different when update pannel is used:
 

<script language="javascript">

<![CDATA[alert("2")]]>

</script>

This is a reason, why the script is not executed. Currently the only way (I know) to workaround this problem is to avoid using of the button-control with UpdatePanel.