[gimp] app: disable overlay scrolling for preferences pages

[Michael Natterer <mitch src gnome org>]

commit 9cbc6d0304d8eca331cddec3b3ca877642eb33e0
Author: Michael Natterer <mitch gimp org>
Date:   Fri Jun 7 12:36:59 2019 +0200

    app: disable overlay scrolling for preferences pages
    
    the overlay was messing with the usability of the page's widgets.

 app/widgets/gimpprefsbox.c | 2 ++
 1 file changed, 2 insertions(+)
---
diff --git a/app/widgets/gimpprefsbox.c b/app/widgets/gimpprefsbox.c
index f845d4048a..4a76d66ab2 100644
--- a/app/widgets/gimpprefsbox.c
+++ b/app/widgets/gimpprefsbox.c
@@ -280,6 +280,8 @@ gimp_prefs_box_add_page (GimpPrefsBox      *box,
   scrolled_win = gtk_scrolled_window_new (NULL, NULL);
   gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (scrolled_win),
                                   GTK_POLICY_NEVER, GTK_POLICY_NEVER);
+  gtk_scrolled_window_set_overlay_scrolling (GTK_SCROLLED_WINDOW (scrolled_win),
+                                             FALSE);
   gtk_box_pack_start (GTK_BOX (page_vbox), scrolled_win, TRUE, TRUE, 0);
   gtk_widget_show (scrolled_win);