Best Answer Martin Davies , 18 December 2013 - 05:24 PM
Actually - further to this. There may be some JS you could use to get the Nav menu to detect if it pushing past the screen. Some code you could use is outlined here http://stackoverflow...lay-off-screen
This would mean changing core code though and adding custom code which we wouldn't be able to support.
I think Ubermenu provides a solution to this built in. http://wpmegamenu.com/Go to the full post