>>369
＞cnt = Selection.Rows.Count
＞Set myRange = Range(Cells(Selection.Rows(1).Row, 12), Cells(Selection.Rows(1).Row + cnt - 1, 12))

Set myRange = Cells(Selection.Row, "L").Resize(Selection.Rows.Count)
もっと簡単に書けそうな気もするがこんなもんかな