Prob Using Macro On Data Validation In Excel

[rob9740]

I'm trying to get each cell in a column to give the user a list to choose from when they click in it. But I also want them to be able to add to the list if the item isn't there. I'm using a data validation list at the moment so is there any way of adding to the data validation list through the use of the drop down list?????

This is what I'm using:

Public Sub CreateCustList()
With ActiveCell
.Validation.Delete
.Validation.Add xlValidateList, , , "=" & "CustomerList"
End With
End Sub

If it's not possible could anybody give me any other suggestions???
Cheers
rob9740