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Elastic Design

This article explains the elastic design capabilities RadEditor offers. The example below shows the simple approach you can use to scale the control by only changing its default font size.

The elastic design capabilities in the RadEditor control are available only when RenderMode is set to Lightweight .

Generally, responsive design means that the page and its content are able to adapt to different screen resolutions without deteriorating the user experience. This often includes changing the font size and having dimensions set in percent.

Elastic Design with RadEditor

Figure 1: Comparison between a RadEditor with the default 12px font size and with increased font-size


RadEditor does not create elastic design by itself, but can fit in a page that follows this pattern.This means that you can change its font size without breaking the control's appearance - if the new size is larger than the original,the elements in the control will simply increase their size.This fluid layout is achieved by using em units for setting dimensions and paddings in the control,instead of px because em units are tied to the font size.This allows dimensions and sizes to scale with the font size.

As of 2016 Q1 SP1 RadEditor takes the font-size of the page automatically. If the developer does not set it explicitly (Example 1), this is up to the client's browser and a common default value is 16px.

Example 1: Setting default font for the page with the default value for the Telerik controls.

body {
    font-size: 20px;
    font-family: "Segoe UI", Arial, Sans-serif;

Example 2: How to increase the font size of a RadEditor as shown in Figure 1.

<style type="text/css">
    div.RadEditor .reToolBarWrapper,
    .reToolBarWrapper .reToolBar,
    div.RadEditor .reToolBar div.reDropDownBody {
        font-size: 18px;


<telerik:RadEditor runat="server" ID="RadEditor1" RenderMode="Lightweight"></telerik:RadEditor>

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