When you are using Internet Explorer, a notification bar will be displayed at the bottom for several tasks you do in the browser.
When you start a download, it shows as a notification. When you complete a download, it notifies you again. The same notification bar also becomes visible when Internet Explorer prompts you to disable addons to improve its performance or when some site is trying to install an ActiveX control. When you delete IE's history or when a popup is blocked, it shows again. When a website becomes unresponsive, IE notifies you again via the notification bar. So this is a very frequently used element of the user interface. Unfortunately, Microsoft made its keyboard usability very poor.
There is a secret hidden shortcut which allows you to close the notification bar directly using the keyboard only. Let's discover it right now.