The Windows Defender developers write on Technet that Windows Defender Beta 2 will be released today:
This update also addresses some issues that have been brought to our attention around signature updating, improves upon the usability of Windows Defender and also improves our SpyNet reporting capabilities.
First off, we have added a checkbox option to continually display the system tray icon. We heard your feedback loud and clear on this one, so those who want to see our icon with the little green check in their system tray as a sign of system health can now do so. We have also improved Windows Defender's ability to report more accurate data about potentially unwanted software through SpyNet so that we can help create better definition updates.