If a keyboard only user attempts to move a course/project site between the three categories ( favorite sites, active sites and archived sites) in the customize tabs section of the preferences tool, they can only move the site between the active and archived sites categories because of the locked my workspace site item. Only when the site is in a specific position in the list can it be moved to the favorite sites category. This issue seems to be dependent on the size of your browser window.
This issue should be rectified so that no matter where in the list the site item resides, it can be moved between the three categories using the keyboard.
I have included a link to a Jing video displaying the issue: http://screencast.com/t/QotJjbomRQA