is it possible to detect a separate click, when clicking on HeaderImage? So default action would be prevented (sorting).
I found this old thread: http://www.telerik.com/forums/display-image-in-gridview-header
Which sort of has a solution but I don't know how to use it when I already have auto-generated "normal" columns. I would prefer just detecting location of HeaderImage though as it seems easier and simpler (if you know how to do it).