You are using a version of the suite that is no longer supported. Furthermore, that version does not support IE 10 nor IE 11. If you want to use the control suite in IE 10 or above, please upgrade to our latest versions and see if the issue will be resolved.
Do you want to have your say when we set our development plans?
Do you want to know when a feature you care about is added or when a bug fixed?
Telerik Feedback Portal
and vote to affect the priority of the items