Comment 153 for bug 527458

Another couple inconsistencies: the panel contains lots of other things,
like applets, and a task switch, that aren't menus, and don't behave like
menus, even though they sort of look like they're on a menu bar.

Also, with a menu bar, you can click once to open the menu, and then move or
drag the mouse to other menus, and have them open. With the indicator
applets, they don't behave this way.. you can't drag between the
application/places/system menus, the indicator-applet menus, the
indicator-applet-session menus, or the clock menu.

If you want a menu bar, with things on it that behave like a menu bar,
that's cool. But you may have to sacrifice the idea of using gnome-panel to
do it. gnome-panel is not a menu bar, and was never designed to act like
one.