When I try to double click on what I think is the thumb in between the two columns I don't get the auto size functionality that I'm expecting. Rather, I get a slight movement on the first click (resize), then I get a sort on the column since the with of the column changed on the first click, my mouse is now on the column header rather than in the middle.
I experimented on the demo site and had the same results.
Please let me know if I'm doing something wrong or if I don't understand something.
(Thanks for the reply - I missed that this is the Silverlight forum, is there an autosize function within the asp.net ajax radgrid?)