I used the Customise Toolbar menu to add the Downloads button permanently to the Safari toolbar, and it's sat there happily until yesterday. The button vanished, and only appears when I'm downloading something. It doesn't appear in the Customise Toolbar menu either, unless there's something in the downloads list. I've tried restarting, reinstalling, and nothing's worked, apart from briefly showing two Downloads buttons which then promptly vanished too. Has anyone else experienced this, or know of a fix? I'm running Safari 5.1.1 on Lion.