diff --git a/gtk/gtkcolorchooser.c b/gtk/gtkcolorchooser.c
index cbefdd3b4a..f3f41fba8f 100644
--- a/gtk/gtkcolorchooser.c
+++ b/gtk/gtkcolorchooser.c
@@ -87,7 +87,7 @@ gtk_color_chooser_default_init (GtkColorChooserInterface *iface)
                             P_("Use alpha"),
                             P_("Whether alpha should be shown"),
                             TRUE,
-                            GTK_PARAM_READWRITE));
+                            GTK_PARAM_READWRITE|G_PARAM_EXPLICIT_NOTIFY));
 
   /**
    * GtkColorChooser::color-activated: