RadControls for ASP.NET AJAX
As the name implies, the Full Screen Mode feature of RadEditor for ASP.NET AJAX allows you to view the editor as you would in a normal fullscreen window.
If you would like to open the editor in full screen mode when the page is loaded, you can use the editor's Fire client-side method to fire the ToggleScreenMode command as shown below:
function OnClientLoad(editor, args)
<telerik:RadEditor runat="server" ID="RadEditor1" OnClientLoad="OnClientLoad">
<Content>Full Screen Mode on Load</Content>