[gtksourceview] check for NULL cat->tooltip_func

[Paolo Borelli <pborelli src gnome org>]

commit 19702e7b40dae1e10095c515d0a77642988d7ebd
Author: Carl-Anton Ingmarsson <ca ingmarsson gmail com>
Date:   Thu Sep 17 14:23:19 2009 +0200

    check for NULL cat->tooltip_func
    
    https://bugzilla.gnome.org/show_bug.cgi?id=595450

 gtksourceview/gtksourceview.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/gtksourceview/gtksourceview.c b/gtksourceview/gtksourceview.c
index 557a95e..d92c565 100644
--- a/gtksourceview/gtksourceview.c
+++ b/gtksourceview/gtksourceview.c
@@ -1230,7 +1230,7 @@ set_tooltip_widget_from_marks (GtkSourceView *view,
 		
 		cat = gtk_source_view_get_mark_category (view, mark);
 
-		if (cat != NULL)
+		if (cat != NULL && cat->tooltip_func != NULL)
 		{
 			GtkWidget *image;
 			GtkWidget *label;