Here's a macro by Bob Phillips and Dave Peterson:

This procedure let's you click on a cell in a range (defined in the code)
and places a "X" in that cell.

Bob Phillips, Dave Peterson

Option Explicit
Private Sub Worksheet_SelectionChange(ByVal Target As Range)
   Dim myHeight As Double
   Application.EnableEvents = False
   On Error GoTo sub_exit
   If Not Intersect(Target, Range("A1:A100")) Is Nothing Then
       With Target
           If .Value = "r" Then
               .Value = ""
           Else
               myHeight = .EntireRow.RowHeight
               .Value = "r"
               .Font.Name = "Marlett"
               .EntireRow.RowHeight = myHeight
           End If
       End With
   End If
sub_exit:
   Application.EnableEvents = True
End Sub

This is sheet code.

Right click the sheet tab and paste into the window that opens.

If you click a cell in the range A1:100 a "X" will be placed in that cell.
If you select that cell again the "X" will be removed.

Biff