Please see the following Forum topic and attached images: http://www.telerik.com/forums/multi-row-tabs#i-uWt1OdnEKceUHt32s43Q We would consider this to be a bug, and the response we received back from Ivan Danchev was less than satisfactory given that this topic is now over 5 years old. Please consider adding this to your roadmap and addressing this behaviour sometime in the near future.
Hello, Thank you for your feedback. Please, note that the Classic rendering is in maintenance mode (as you can read in this blog post - http://www.telerik.com/blogs/spreadsheet-and-modern-rendering-in-ui-for-asp.net-ajax) and we could fix only critical problems. This is not a critical one, since it is already fixed and not reproducible in the new modern Lightweight render mode of the control. Can you please switch the render mode to lightweight and let us know whether you experience any problems? We will be glad to help you resolve them. Regards, Dimitar Goshev