Hi Duy,
You can try manually registering the the css styles for the controls that you use. RadControls' styling relies on:
1. A
base css stylesheet which can be found at your local installation of Telerik controls in the
Skins folder. It is named after the control. For example -
Menu.css or
Toolbar.css. By default, the base stylesheet is served as embedded resource. However, you can manually register it by setting
EnableEmbeddedBaseStylesheet="false" and referencing the base css in your page
2.
Skin specific css stylesheet and images, which by default also come from the Telerik.Web.UI assembly. However, you can manually register a skin following this topic:
http://www.telerik.com/help/aspnet-ajax/skinregistration.html
Please, try these suggestion and let us know if the problem persists.
Regards,
Peter
the Telerik team