i am creating a custom control (RCB) that extends RadComboBox.
i want to add a child control(textbox) for the RCB, so whenever an RCB is created,  a textbox will be created.
i managed to do this by overrideing OnPagePreLoad of RadComboBox, and add Page.Form.Controls.Add(textbox);

everything works fine (ie. textbox is created with every RadComboBox) untill i use RCB in a gridview edit panel (where only RadComboBox is created  and not the textbox).

how can i fix this issue?is there a better way to add a control to another control?

telerik:RadWindowManager ID="RadWindowManager1" runat="server">

</telerik:RadWindowManager>

<telerik:RadAjaxManager ID="RadAjaxManager1" runat="server" UpdatePanelsRenderMode="Inline">

<AjaxSettings>

<telerik:AjaxSetting AjaxControlID="RadGridBulkCharts">

<UpdatedControls>

<telerik:AjaxUpdatedControl ControlID="RadGridBulkCharts" LoadingPanelID="RadAjaxLoadingPanel1" />

</UpdatedControls>

</telerik:AjaxSetting>

<telerik:AjaxSetting AjaxControlID="chkBulk">

<UpdatedControls>

<telerik:AjaxUpdatedControl ControlID="chkBulk" LoadingPanelID="RadAjaxLoadingPanel1" />

</UpdatedControls>

</telerik:AjaxSetting>

<telerik:AjaxSetting AjaxControlID="RadGridEDLogFiles">

<UpdatedControls>

<telerik:AjaxUpdatedControl ControlID="RadGridEDLogFiles" LoadingPanelID="RadAjaxLoadingPanel1" />

</UpdatedControls>

</telerik:AjaxSetting>

<telerik:AjaxSetting AjaxControlID="chkEDLog">

<UpdatedControls>

<telerik:AjaxUpdatedControl ControlID="chkEDLog" LoadingPanelID="RadAjaxLoadingPanel1" />

</UpdatedControls>

</telerik:AjaxSetting>

</AjaxSettings>

</telerik:RadAjaxManager>

<telerik:RadAjaxLoadingPanel ID="RadAjaxLoadingPanel1" runat="server">

</telerik:RadAjaxLoadingPanel>
<code>

Notice I have the client code commented out which I said works fine just to see if it gets into the page_load event of the child page. It does from the client side (when the code is uncommented), but from the server side, the Load event is not hit.

Here is my abbreviated server side code in the event once the onclick event happens:
<code>

protected void Chart_Click(object sender, ImageClickEventArgs e)
        {
           
            file = new FileInfo(ChartPath + imgName);
            string cpPath = (string)settingsReader.GetValue("tmpImageFolder", typeof(String)) + ViewState["UserName"].ToString();

            if (file.Exists)
            {
                if (!Directory.Exists(cpPath))
                {
                    Directory.CreateDirectory(cpPath);
                }

                file.CopyTo(cpPath + file.Name, true);

                RadWindowManager1.Windows.Clear();
                RadWindow newwindow = new RadWindow();
                newwindow.ID = "RadWindow1";
                newwindow.ShowContentDuringLoad = false;
                newwindow.Width = Unit.Pixel(1000);
                newwindow.Height = Unit.Pixel(600);
                newwindow.Title = "View Chart Image";
                newwindow.Behaviors = WindowBehaviors.Default;
                newwindow.Skin = "Outlook";
                newwindow.Modal = true;
                newwindow.VisibleOnPageLoad = true;
                newwindow.NavigateUrl = "../scan/viewChart.aspx";
                newwindow.Visible = true;
                RadWindowManager1.Windows.Add(newwindow);

            }
        }