Rad Editor Control in Rad Window retrieves page CSS files multiple times

4 posts, 0 answers
  1. chintan
    chintan avatar
    5 posts
    Member since:
    Mar 2011

    Posted 09 Aug 2015 Link to this post

    Hello Support,

    ​We are experiencing very sluggish rendering behavior when using Rad Editor Control in Rad Window when browsed from IE browser.
    Please find few image screenshots to explain the issue.

    Test environment:
    Telerik version: 2015.1.401.45
    Chrome: 44.0.2403.130
    IE: 11.0.9600.17905

    It seems that page CSS files are being retrieved multiple times from the server in all browsers but in IE, files are retrieved twice or more than twice. Hence slows down the whole page in IE browser.

    Brief information about existing application (I don’t think it is related to Kentico environment which we are using):

    • user control (deployed as Kentico webpart) which is added to Kentico Page
    • has RadGrid for listing items.
    • editing item from the grid, pop-ups Rad Window.
    • Rad Window has editable form fields along with 7 Rad Editors


    Investigation so far:

    • Remove rad Editors from the rad window – No duplication of the CSS files
    • Specified “EditorCssFile” as well as “CssClasses” – Still retrieves CSS files

    Need your help to fix the rendering/retrieving difference between browsers as well as any workaround to stop retrieving CSS files multiple times.

    Please let me know if you need any other information.




    Isolated page code:


    <%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="RadEditor_RadWindow_PageStyle.Default" %>
    <!DOCTYPE html>
    <head runat="server">
        <link href="Content/Site.css" rel="stylesheet" />
        <form id="form1" runat="server">
                <asp:ScriptManager ID="scmScriptManager" runat="server"></asp:ScriptManager>
                    <asp:Button ID="btnOpen" runat="server" Text="Open" OnClick="btnOpen_Click" />
                    <telerik:RadWindow ID="radWindow" runat="server" Modal="true" Behaviors="Close" AutoSize="true"
                            <p>Rad Editor 1</p>
                                <telerik:RadEditor ID="RadEditor1" runat="server" Width="600px" Height="300px"
                                    EditModes="Design" Visible="false">
                            <p>Rad Editor 2</p>
                            <telerik:RadEditor ID="RadEditor2" runat="server" Width="600px" Height="300px"
                                    EditModes="Design" Visible="false">


    using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Web;
    using System.Web.UI;
    using System.Web.UI.WebControls;
    namespace RadEditor_RadWindow_PageStyle
        public partial class Default : System.Web.UI.Page
            protected void Page_Load(object sender, EventArgs e)
            protected void btnOpen_Click(object sender, EventArgs e)
                radWindow.VisibleOnPageLoad = true;

  2. chintan
    chintan avatar
    5 posts
    Member since:
    Mar 2011

    Posted 11 Aug 2015 Link to this post

    Hello Support, 

    Is there any update on this issue? Are you able to replicate the behaviour?

    Do you need any other information?




  3. Niko
    Niko avatar
    404 posts

    Posted 12 Aug 2015 Link to this post

    Hi Chintan,

    The easiest way is to use ContentAreaMode="Div" of the RadEditor control.

    Otherwise, when you use an Iframe ContentAreaMode, the Editor tries to copy all the styles from the page within the iframe so that it preserves the look and feel of the content. You can prevent this by adding at least one file in the CssFiles collection.

    My recommendation is to go with the ContentAreaMode="Div". The Editor control will only render a simple <div> element with editable content and no styles will be copies.

    Hope this helps.

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  4. chintan
    chintan avatar
    5 posts
    Member since:
    Mar 2011

    Posted 13 Aug 2015 in reply to Niko Link to this post

    Thanks Niko,

     Specifying ContentAreaMode to "Div" seems to be working. Thanks for the help again.



    Chintan Desai.

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