Hi Got,
I don't know of a built-in feature that fills to the right comparable to the fill down that occurs when you double-click on a fill handle. But here is a simple macro that does such a fill.
Code:
Sub RowFill()
Selection.AutoFill Range(Selection(1), _
Selection(1).Offset(-1).End(xlToRight).Offset(1))
End Sub
Simply select the row of cells that start the fill, then run the macro and it will fill to the end of the filled portion of the row above it. I would recommend assigning a keyboard shortcut to this macro (for example Ctrl-r) to make it easy to use.
Keep Excelling.
Damon