Sub Activity_KeyPress (KeyCode As Int) As Boolean 'return true if you want to consume the event If KeyCode = KeyCodes.KEYCODE_BACK Then If Msgbox2("Do you want to close?", "", "Yes", "Cancel", "No", Null) = DialogResponse.POSITIVE Then ' Return False ExitApplication 'App is exiting Else Return True End If End If End Sub **** The BACK back button shows that the tween has not finished.