Using framework 3.5, I get an error when I drop a combobox from the toolbox in visual mode.
Unable to load telerik.web.ui or dependency.
I have not the pb with RadTextBox, I have in my references the framework 3.5 version of telerik.web.ui.
Our developers managed to fix part of the problem - design time under VS 2008, used on Windows XP machine. Unfortunately, the problem with Windows Vista and VS 2008 still remains.
If you are using Windows XP and want to receive a hotfix which addresses the problem, please open a support ticket.
We hope that the design time problem with Windows Vista and VS 2008 will be solved in the next service pack of the "Prometeus" controls.