It is hard to say why you are facing problems with this feature based on the information provided. Please note that that with the Q3 2012 official release (expected for the mid-October) you will no longer receive future updates, new features and installations for WPF 3.5 and Silverlight 4 controls. You can read here
for more information.
I strongly reccomend that you migrate to our latest version so that you will be able to access the latest hotfixes and new features of our controls.
On a side note - this forum post was opened for questions regarding RadChart for WinForms. Please consider asking yours in the forum threads with relevant Product and Technology used.
the Telerik team
You’ve been asking for it and now it’s time for us to deliver. RadControls for WinForms Q3 2012 release is just around the corner. Sign up for a free webinar
to see first all the latest enhancements.