Error:

Problem:

By default “Spell check” button uses “AjaxSpellCheck” not “SpellCheck “

  <telerik:EditorTool Name="SpellCheck" Enabled="true" />

Solution:

Use AjaxSpellchek

   <telerik:EditorTool Name="AjaxSpellCheck" Enabled="true" />

ASP.Net 4.5 introduced more options to the Text Mode property: Color, Date, DateTime, DateTimeLocal, Email, Month, Number,Range, Search, Phone, Url, Week

But remember all these new options will work only with browsers supporting these HTML5 features (Ex: IE 10). For all other browsers these textbox's will behave as normal textbox.

Ps: Here is a nice website, where you can test your browser HTML5 features: http://html5test.com/

Problem:

RadEditor Content not saved on page postback.

Solution:

Add UseSubmitBehavior="false" to the button that’s causing page postback.

<asp:Button ID="Button1" runat="server" 
OnClick="Button1_Click" Text="Button1"  UseSubmitBehavior="false"  />