Workbook_SheetActivate(ByVal Sh As Object) QUESTION...

Hello people,
1- Copy following code into Sheet1 module.

Private Sub Worksheet_Activate()
MsgBox "Hello"
End Sub

2- See MessageBox When you click Sheet1.

3- Copy following code into ThisWorkbook module.

Private Sub Workbook_SheetActivate(ByVal Sh As Object)
MsgBox "Hello"
End Sub

4-See MessageBox When you click any of sheets.

Question: How to change above code to work only Sheet1 clicking?