Activate vbCancel in message box

Hi there
I'm using a message box to unhide some sheets in my workbook and want to be able to cancel the command when I have unhidden the ones I want. I'm using the code below and though it seemed to work a few times, it won't do so now. Can anyone tell me how I can correct it?

Thanks in advance for any help.

datafiend

Sub UnhideSomeSheets()
    Dim sSheetName As String
    Dim sMessage As String
    Dim Msgres As VbMsgBoxResult
    Dim wsSheet As Worksheet

    For Each wsSheet In ActiveWorkbook.Worksheets
        If wsSheet.Visible = xlSheetHidden Then
            sSheetName = wsSheet.Name
            sMessage = "Unhide the following sheet?" _
              & vbNewLine & sSheetName
            Msgres = MsgBox(sMessage, vbYesNoCancel)
            If Msgres = vbYes Then wsSheet.Visible = xlSheetVisible
           ElseIf Msgres = vbCancel Then Exit Sub
      
        End If
 
    Next wsSheet
End Sub