This update fixes a number of issues including the annoying Shift + space bug that has been the plague of messages on Twitter for a while now.
There is also a couple of new methods including a one for knowing if the user launched the application or it was launched on system startup. To take advantage of these new methods you will have to change you Application Descriptor File to use Adobe AIR 1.5.1.
So get out there and grab yourself the latest AIR version : http://get.adobe.com/air/