diff --git a/src/hdeq.c b/src/hdeq.c
index 14390d7..ccf61ce 100644
--- a/src/hdeq.c
+++ b/src/hdeq.c
@@ -110,6 +110,8 @@
 
 #define NOTCH_PASS_WIDTH              75
 
+GtkNotebook *l_notebook1;
+
 
 void interpolate (float, int, float, float, int *, float *, float *, float *, 
                   float *);
diff --git a/src/hdeq.h b/src/hdeq.h
index 27c9d34..49fad45 100644
--- a/src/hdeq.h
+++ b/src/hdeq.h
@@ -61,7 +61,7 @@ void hdeq_notebook1_set_page (guint page_num);
 int get_current_notebook1_page ();
 
 
-GtkNotebook *l_notebook1;
+extern GtkNotebook *l_notebook1;
 
 
 #endif