Comment 16 for bug 635223

> Why isn't Unity doing the exact thing Gnome is here?

Because Unity is not centered around a hierarchical menu like Gnome is. We only support one level of categories (ie no submenus) and the categories are lined up horizontally, not vertically, which makes them fill up the available space quickly - ie. we can not just start arbitrarily adding elements to the end of the category list - it would overflow the screen.

Also the browsing and searching is integrated with the software center with all available apps. Which means that a category can easily contain hundreds of items (even thousands), not just the few handfuls you see on a desktop installation.

These features gives Unity some requirements that does not integrate particularly well with the whole XDG menu spec or how Gnome does things. Not saying it's impossible, but just that we can't simply take libgnome-menu off the shelf and be happy.