Select the current color of a GtkColorButton should be selected in the
GtkColoroChooserDialog which is shown when the color button is clicked.
https://bugzilla.gnome.org/show_bug.cgi?id=676198
gtk_color_chooser_set_use_alpha (GTK_COLOR_CHOOSER (button->priv->cs_dialog),
button->priv->use_alpha);
+ gtk_color_chooser_set_rgba (GTK_COLOR_CHOOSER (button->priv->cs_dialog),
+ &button->priv->rgba);
+
gtk_window_present (GTK_WINDOW (button->priv->cs_dialog));
}