Blow it up.
Why would they possibly need the latest kernel version?
Because the people who write the requirements need to justify their jobs.
As others have said, the first thing I do in Windows is turn off window grouping, and in firefox is turn off all the extraneous, real estate-sucking bars they haven enabled.
I suggest that they implement whichever solution(s) they like as an extension, and let people vote with their downloads which one they like best before drastically changing the browser. Let the users decide.
A successful [software] tool is one that was used to do something undreamed of by its author. -- S. C. Johnson