I don't know how to call this, the icon that indicated "this item is being seleted" in some pop-up menus is missing and replaced by a question mark. Plz see the pics. It's not just the system's default software. It is missing in every apps including third party apps. I know that a reinstallation of the OS would have good chance to fix this issue, but everything else is running fine ans smoothly. I dont think it is worth doing a reinstallation for just fixing this tiny (but annoying) problem. I guess perhaps the icon image file is broken or corrputed during the installation. But if you know what happened please tell me thanks.