Dropping the selection markers manipulates the selection which plays

havoc in multiple scribe instances...

Chrome handles the selection fine but Firefox requires the manipulation.
It looks like these used to surround the isFFBug check, which makes sense as that test is looking for the markers. Not sure what that was meant to represent -- checking if the selection is in the scribe instance?

Your new code expects the scribe marker to be there even though they haven't been dropped in?