Always show menu images
There is a GtkSetting [1] that controls whether images in menus are shown or not. On some distributions it is enabled by default and on others it is disabled by default. To force show images in menus set the 'always-show-image' property to true in Gtk::ImageMenuItems [2].
References:
-
Gtk3 Reference Documentation - Settings/gtk-menu-images
https://developer.gnome.org/gtk3/stable/GtkSettings.html#GtkSettings--gtk-menu-images -
Gtk3 Reference Documentation - GtkImageMenuItem
https://developer.gnome.org/gtk3/stable/GtkImageMenuItem.html#gtk-image-menu-item-set-always-show-image