A list of icon sizes. The list is separated by colons, and item has the form:
E.g. “gtk-menu=16,16:gtk-button=20,20:gtk-dialog=48,48”. GTK+ itself use the following named icon sizes: gtk-menu, gtk-button, gtk-small-toolbar, gtk-large-toolbar, gtk-dnd, gtk-dialog. Applications can register their own named icon sizes with gtk_icon_size_register().
This setting is ignored.