Hide and Unhide rows on multiple sheets based on a validation list on a single sheet

If you doubleclick "ThisWorkbook" in vba editor and paste this code, it will work for all sheets when you change the value of B1:

Private Sub Workbook_SheetChange(ByVal Sh As Object, ByVal Target As Range)

Dim lr As Long
Dim i As Long

If Not Intersect(Target, Sh.Range("B1")) Is Nothing Then
    Sh.Cells.EntireRow.Hidden = False
    lr = Sh.Range("A" & Rows.Count).End(xlUp).Row
    For i = 2 To lr
        If Sh.Range("A" & i).Value <> Sh.Range("B1").Value Then Sh.Range("A" & i).EntireRow.Hidden = True
        If Sh.Range("A" & i).Value = Sh.Range("B1").Value Then Sh.Range("A" & i).EntireRow.Hidden = False
    Next i
End If

End Sub