bandit's code needs to go in the worksheet module(s) for the sheet(s) of interest.
Right click the sheet tab and choose View code. Paste bandit's code in the white area that is the sheet code module.
Press AltQ to get back to your sheet. (Repeat for any other sheets you want this to work on.) If you have a "boatload" of sheets and want to assign this to every sheet in the workbook, you can do it in the ThisWorkbook module.
That code would look like:
Private Sub Workbook_SheetActivate(ByVal Sh As Object)