This inconsistency of the docs was pointed out by
Pierre-Yves Luyten in bug 680949.
* @widget: the object which received the signal.
*
* The ::color-set signal is emitted when the user selects a color.
- * When handling this signal, use gtk_color_button_get_color() and
- * gtk_color_button_get_alpha() (or gtk_color_button_get_rgba()) to
+ * When handling this signal, use gtk_color_button_get_rgba() to
* find out which color was just selected.
*
* Note that this signal is only emitted when the <emphasis>user</emphasis>