[gnumeric] Gui: use a proper GtkSeparatorMenuItem

[Morten Welinder <mortenw src gnome org>]

commit f8525bab5fbd5fdd3ddb23cd2e90976e6d7be50c
Author: Morten Welinder <terra gnome org>
Date:   Sat Nov 17 21:12:10 2018 -0500

    Gui: use a proper GtkSeparatorMenuItem
    
    Using an empty item was probably a remnant from gtk 1.2 or thereabouts.

 ChangeLog      | 3 +++
 src/gui-util.c | 3 +--
 2 files changed, 4 insertions(+), 2 deletions(-)
---
diff --git a/ChangeLog b/ChangeLog
index 0d9508a51..678ea9a30 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2018-11-17  Morten Welinder  <terra gnome org>
 
+       * src/gui-util.c (gnm_create_popup_menu): Use a
+       GtkSeparatorMenuItem instead of an empty item.
+
        * src/func.c (gnm_func_set_varargs): Correctly signal a vararg
        function by setting max argumnets to maxint.
 
diff --git a/src/gui-util.c b/src/gui-util.c
index f5fd0a57b..069811671 100644
--- a/src/gui-util.c
+++ b/src/gui-util.c
@@ -690,8 +690,7 @@ gnm_create_popup_menu (GnmPopupMenuElement const *elements,
                        }
                } else if (elements->index >= 0) {
                        /* separator */
-                       item = gtk_menu_item_new ();
-                       gtk_widget_set_sensitive (item, FALSE);
+                       item = gtk_separator_menu_item_new ();
                }
 
                if (elements->index > 0) {