Comment 43 for bug 878492

I've tracked it down to org.gnome.desktop.interface menubar-accel dconf key. It defaults to F10, so gnome apps are affected.
/desktop/gnome/interface/menubar_accel is the legacy gconf key.

Additionally, for gnome-terminal to actually forward F10 key press to the shell, /apps/gnome-terminal/global/use_menu_accelelators needs to be disabled. That in itself looks like a bug in gnome-terminal (it should read the key above and only act on the shortcut set there).

A side-effect that I didn't yet identify is, after changing the accel key, F10 triggers the context menu in gnome apps.