Video made by en user Atethnekos
As illustrated in the attached video, VE's drag and drop function has some odd quirks in Firefox. One can select items from below the VE surface, such as the MediaWiki logo or the licensing disclaimer text, and drag them into the VE surface. These items can only be added to the last line of an article. Items seem to be added as bulleted items, increasing indent with each addition.
Tested on FF 24 Win 7 with Monobook, duplicated with FF 24 and Mac OS 10.6
Could not duplicate using Chrome on the above Mac OS - may be a Firefox issue.