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