Comment 4 for bug 912679

It can't be an issue with the global menu rendering, because the rendering system can't possibly tell which menu items are for hiding an in-window menu bar and which aren't. (It could try, by looking for the string "Menu Bar" or "Menubar", but the menus might not be in English.)

XChat needs to not have a "View" > "Menu Bar" item, when running in Unity, for exactly the same reason as XChat Azure doesn't have a "View" > "Menu Bar" item on Mac OS X.