Try the workbook module instead

Private Sub Workbook_SheetActivate(ByVal Sh As Object)
If ActiveSheet.Name = "Sheet1" Or ActiveSheet.Name = "Sheet2" Then
MsgBox "Your toolBar Macro Here" 'change to Call CreateMenubar
End If
End Sub

Private Sub Workbook_SheetDeactivate(ByVal Sh As Object)
MsgBox "Your remove toolbar Macro Here" ' change to Call RemoveMenubar
End Sub