docs: add missing info for gtk_widget_get_style_context()

It is important to know whether the returned object can or cannot
change, for a certain widget. For example to connect to the
GtkStyleContext::changed signal.

https://bugzilla.gnome.org/show_bug.cgi?id=769047

diff --git a/gtk/gtkwidget.c b/gtk/gtkwidget.c
index a8ad23284dd0a0654bfa8174a2178cd05344f20f..52a999574141d6daaace716704847c04589d89fa 100644 (file)
--- a/gtk/gtkwidget.c
+++ b/gtk/gtkwidget.c
@@ -16542,7 +16542,8 @@ _gtk_widget_peek_style_context (GtkWidget *widget)
  * gtk_widget_get_style_context:
  * @widget: a #GtkWidget
  *
- * Returns the style context associated to @widget.
+ * Returns the style context associated to @widget. The returned object is
+ * guaranteed to be the same for the lifetime of @widget.
  *
  * Returns: (transfer none): a #GtkStyleContext. This memory is owned by @widget and
  *          must not be freed.