We are deeply sorry for the troubles caused.
The breaking changes have been noted in the Q1 2008 Release Notes
where you can also find a PDF document and what has been changed. In case you are not RSS-subscribed to this page, I will suggest doing so in order to stay on top of what changes with each new version.
I have just posted a blog and sticky forum post in the RadGridView section on the matter: Breaking changes in RadGridView for WinForms Q1 2008
. I hope this will help other people who are having the same problem.
Let us know if we can be of further assistance.
the Telerik team