Private Sub UserForm_Activate()

ListBox1.RowSource = Range("Pneumatics").Address

End Sub

Private Sub ListBox1_Click()

Select Case ListBox1.ListIndex

Case 0
ListBox1.ListIndex = -1 'deselect the selected value
ListBox1.RowSource = "" ' clear the list
ListBox1.RowSource = Range("Frames").Address ' repopulate the list
Case 1
'...more stuff...
Case 2
'...more stuff...
End Select

End Sub

Private Sub ListBox1_MouseUp(ByVal Button As Integer, _
        ByVal Shift As Integer, _
        ByVal X As Single, _
        ByVal Y As Single)
       
With ListBox1
    'Button will = 1 for left-click
    If Button = 1 Then
        Select Case .ListIndex
        Case 0
            .ListIndex = -1
            .RowSource = ""
            .RowSource = Range("Frames").Address

        Case 1
       
        Case 2
       
        Case Else
        End Select
    End If
End With
End Sub