Comment 37 for bug 775702

I don't know but bug
https://bugs.launchpad.net/inkscape/+bug/1066573
Says, it it works (unless desktop-wide disabled via gtk settings for all menus).

So maybe, but probably not ;) (just a wild guess!) Could it have something to do with buttons-have-icons settings:

http://www.iloveubuntu.net/how-change-your-icon-theme-fonts-gtk-theme-dconf-editor-and-gnome-tweak-tool