researched in this forum and found a solution that solves part of my problem in this link:
http://blogs.telerik.com/pavelpavlov/posts/09-12-04/adding_additional_power_to_radgridview_for_silverlight_with_attached_behaviors.aspx
I wonder if there is already ready solution for headers grouped into various levels and in the attached.
I wonder if there is already ready solution for headers grouped into various levels and in the attached.