Do RadControls support Unicode characters? ANSWER
RadControls support Unicode encoding, which makes it compatible with Cyrillic, Greek, Asian, Arab, etc. characters. Developers can even control the encoding manually by setting the FileEncoding property (by default this property is set to "65001" which corresponds to the UTF-8 encoding) which applies to the scenario when the HTML content is saved directly in the ascx/aspx file. You could also change the encoding of the used XML files by setting the encoding attribute at the top in the respective xml file. By default it is set to UTF-8 (code page 65001).
Sample XML example (taken from the German localization files of RadEditor) <?xml version="1.0" encoding="utf-8" ?>