do you know what "upset" really means ????
It means that Sitefinity is presented as part of Telerik but these really excellent Telerik components do not work within Sitefinity. Can you Sitefinity definitely tell us, if and when you will correct this strong issue?
RAD ASP.NET AJAX tools worked very well until Sitefinity 3.7 and do not longer since Sitefinity 4.0 rollout !!!!
Developers be careful and do not try to embed Teleriks grids, navigation, scheduler and so on into your projects. You only will get a lot of error messages.
I tried to get a positive answer from Sitefinity since rollout on January 2011 but I did not get an answer that would be positive. - Then I was in hope that it would be solved with SP1. - Did not!!!! Sitefinity's messages: "We are working an this issue" is too less .....