Similar behavior to the one you describe was observed in older version of the controls. However, the issue has been fixed and is not observed in the latest version.
Ensure that you are using the latest release of the controls and the issue should be resolved. Currently the latest version is 2014.3.1209.
Check out the Telerik Platform - the only platform that combines a rich set of UI tools with powerful cloud services to develop web, hybrid and native mobile apps.