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

Ok, how about this, but please note you need to change 2 lines of code to have the "Sheet1_After" part changed to the name of your actual sheet with pulldown. It still goes in the code for "ThisWorkbook":

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 And Sh.Name = "Sheet1_After" Then 'change "Sheet1_After" to whatever the name of the sheet with the pulldown is
    For Each ws In ThisWorkbook.Sheets
        If ws.Name <> "Validation_List" Then 'exclude validation list sheet
            ws.Cells.EntireRow.Hidden = False
            lr = ws.Range("A" & Rows.Count).End(xlUp).Row
            If ws.Name = "Sheet1_After" Then 'change to name of theet with pulldown, it will do row 3 and on for this sheet since layout is different
                For i = 3 To lr
                    If ws.Range("A" & i).Value <> Sh.Range("B1").Value Then ws.Range("A" & i).EntireRow.Hidden = True
                    If ws.Range("A" & i).Value = Sh.Range("B1").Value Then ws.Range("A" & i).EntireRow.Hidden = False
                Next i
            Else
                For i = 2 To lr
                    If ws.Range("A" & i).Value <> Sh.Range("B1").Value Then ws.Range("A" & i).EntireRow.Hidden = True
                    If ws.Range("A" & i).Value = Sh.Range("B1").Value Then ws.Range("A" & i).EntireRow.Hidden = False
                Next i
            End If
        End If
    Next ws
End If

End Sub