Focus is lost when GenerateEditingElement is overridden

When deriving from DataGridBoundColumn to override control creation for your DataGrid, you are going to face a problem.. Where does my focus go when I double click the cell?

The cell control is created and activated but the focus just goes to the parent DataGridCell leaving the control that I just created in GenerateEditingElement unfocused. So I will have to click a third click to get the focus where I wanted it in the first place.

The solution is to override DataGridBoundColumn.PrepareCellForEdit and set the focus there. Voila.