Single And Multiple Choice Dropdowns In Same Worksheet

I've finally figured out the correct code to allow multiple selections from one of my drop down lists. Now, when I try selecting an item from a separate list (which I only want to be able to choose one thing), it's accepting multiple items. How do I have both working properly?

This is the code I have for my multiple selection list (which is only in column M):

Private Sub Worksheet_Change(ByVal Target As Range)
Dim rngDV As Range
Dim oldVal As String
Dim newVal As String
If Target.Count > 1 Then GoTo exitHandler
On Error Resume Next

[code]...