Is there a way in XUL framework not to autohide menubars by default

Hello guys, for almost a week I'm looking the way of to show menus in xul app by default. 

What is the proper way to do this, by settings maybe. 

Or I should manually perform this in js after any window.open() instruction? 

NB. My exact trouble is to switch by default on all menus in thunderbird. 

Thank you, 
Ivan