Trying to re-design Glade again, this time with some progress

I'm trying to re-design Glade to use app-menu and header-bar like in
this mock-up:

https://raw.github.com/gnome-design-team/gnome-mockups/master/gedit/gedit-menus-v3.png

Current state:

http://wstaw.org/m/2013/12/06/Screenshot_from_2013-12-06_120223.png

(it requires https://bugzilla.gnome.org/show_bug.cgi?id=719801 for thin
pane separators)

I have some questions:

* Why is the new tab button called just "New", not "New Tab"?
* Why isn't there redo or redo history in the mockup? Am I missing
something?
* Where to put cut, copy, paste; move, margin, alignment; and preview
buttons?
* About margin editing, is it even useful? You usually want to specify
exact pixel margins (eg. 6 or 12).