After more than 10 years this is STILL a Bug. 

https://feedback.telerik.com/winforms/1369181-fix-radgroupbox-with-collapsed-header-does-not-fill-the-entire-content-if-there-is-a-docked-child-control-inside-the-groupbox

The groupbox header does not collapse when I put a table layout panel inside of it.

Is this product (Telerik for winforms) still being supported? Or should I be looking elsewhere for a different controls toolkit solution for my company?