(ASP.NET 2.0 - GridView) Strange behavior!

[Kursat]

Hi,

I added "Select" column to a GridView to enable row selection. It works well
if ButtonType property of the "Select" column is "Link" but If I set
ButtonType property to "Image" and click that image to select a row, page is
being posted back twice and SelectedIndexChanged event is also being fired
twice. Is this normal behavior, bug or resulted by other page or control
settings?

Thanks in advance.