This should do the trick I think...
Private Sub cboLimitToList_Change()
Dim slText As String
Dim ilN As Integer
Dim ilLen As Integer
If cboLimitToList.Text = "" Then
Exit Sub
End If
slText = cboLimitToList.Text
ilLen = Len(slText)
For ilN = 0 To cboLimitToList.ListCount - 1
If slText = Mid(cboLimitToList.List(ilN), 1, ilLen) Then
Exit Sub
End If
Next
cboLimitToList.Text = ""
End Sub