diff -upr mate-control-center/font-viewer/font-view.c mate-control-center-test/font-viewer/font-view.c
--- mate-control-center/font-viewer/font-view.c	2015-08-30 12:15:26.180405369 +0200
+++ mate-control-center-test/font-viewer/font-view.c	2015-08-30 12:11:59.432282000 +0200
@@ -425,7 +425,7 @@ info_button_clicked_cb (GtkButton *butto
 
     populate_grid (self, grid, face);
 
-    dialog = gtk_dialog_new_with_buttons (NULL, GTK_WINDOW (self->main_window),
+    dialog = gtk_dialog_new_with_buttons ("", GTK_WINDOW (self->main_window),
                                           GTK_DIALOG_MODAL | GTK_DIALOG_DESTROY_WITH_PARENT,
                                           GTK_STOCK_CLOSE, GTK_RESPONSE_CLOSE,
                                           NULL);