[gtk+/wip/csoriano/pathbar-prototype: 145/167] gtkcontainer: clarify requirements for implementations

[Carlos Soriano Sánchez <csoriano src gnome org>]

commit 958f1a00e085658172945b31dffcb8c8c4e8e540
Author: Carlos Soriano <csoriano gnome org>
Date:   Wed Nov 11 11:37:28 2015 +0100

    gtkcontainer: clarify requirements for implementations
    
    Spent quite a few time investigating why the widgets were
    not shown in my GtkContainer implementation.

 gtk/gtkcontainer.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkcontainer.c b/gtk/gtkcontainer.c
index 30a6d1e..45480fe 100644
--- a/gtk/gtkcontainer.c
+++ b/gtk/gtkcontainer.c
@@ -80,6 +80,9 @@
  * children in a horizontal row, and a #GtkGrid arranges the widgets it contains
  * in a two-dimensional grid.
  *
+ * For implementations of GtkContainer only the virtual method gtk_container_forall
+ * is required, since it's used for painting and realizing children.
+ *
  * # Height for width geometry management
  *
  * GTK+ uses a height-for-width (and width-for-height) geometry management system.