<p>For more information, see <a href="http://blog.flexexamples.com/2007/12/23/customizing-the-background-alpha-and-background-color-of-the-alert-control-in-flex/">http://blog.flexexamples.com/2007/12/23/customizing-the-background-alpha-and-background-color-of-the-alert-control-in-flex/</a>.</p>