DetailItemTemplate is considered a part of the GridDataItem and is rendered in a
new row right after the GridDataItem itself. The template is instantiated within
a single cell that spans over the whole row/item.
There is a new item type in RadGrid - GridItemType.DetailTemplateItem. Due to the
fact that the GridDetailTemplateItem is an integral part of the GridDataItem, ItemCreated
and ItemDataBound events won't be triggered when it is created/bound. It is possible,
however to get all items of type GridDetailTemplateItem by using the GetItems method
of the GridTableView.