https://bugzilla.gnome.org/show_bug.cgi?id=779653#c33
and this is closer to what gtk-3-22 says anyway.
*
* GtkFrame has a main CSS node with name frame. This node can be given the
* style class .flat, which is used by themes to disable drawing of the border.
- * Another way to do this in code is to call gtk_frame_set_shadow_type() with
- * GTK_SHADOW_NONE to add the .flat class or any other shadow type to remove it.
+ * To do this from code, call gtk_frame_set_shadow_type() with %GTK_SHADOW_NONE
+ * to add the .flat class or any other shadow type to remove it.
*/
struct _GtkFramePrivate