Private Sub Worksheet_BeforeDoubleClick(ByVal Target As Range, Cancel As Boolean)
Application.ScreenUpdating = 0
If Not Intersect(Target, Range("D10:D100")) Is Nothing Then
Target.Value = IIf(Target.Value = "", "X", "")
If Target.Value = "X" Then
Target.Offset(0, 1).Value = "Action " & Application.CountIf(Range(Cells(11, 3), Cells(Target.Row, 3)), Cells(Target.Row, 3)) & " :"
Else: Target.Offset(0, 1).Value = ""
End If
End If
Application.ScreenUpdating = 1
End Sub