[gimp/gimp-2-8] app: allow to pass NULL to gimp_window_set_primary_focus_widget() (cherry picked from commit 754e4eb

[Michael Natterer <mitch src gnome org>]

commit 3aaa69642e218cb495a2cc6691368a901df26e18
Author: Michael Natterer <mitch gimp org>
Date:   Wed Apr 10 19:28:49 2013 +0200

    app: allow to pass NULL to gimp_window_set_primary_focus_widget()
    (cherry picked from commit 754e4eb91946ebb70ff1f6e81e8e7a694d81573d)

 app/widgets/gimpwindow.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/app/widgets/gimpwindow.c b/app/widgets/gimpwindow.c
index 0cdb7ab..ce6ce19 100644
--- a/app/widgets/gimpwindow.c
+++ b/app/widgets/gimpwindow.c
@@ -168,8 +168,9 @@ gimp_window_set_primary_focus_widget (GimpWindow *window,
                                       GtkWidget  *primary_focus)
 {
   g_return_if_fail (GIMP_IS_WINDOW (window));
-  g_return_if_fail (GTK_IS_WIDGET (primary_focus));
-  g_return_if_fail (gtk_widget_get_toplevel (primary_focus) ==
+  g_return_if_fail (primary_focus == NULL || GTK_IS_WIDGET (primary_focus));
+  g_return_if_fail (primary_focus == NULL ||
+                    gtk_widget_get_toplevel (primary_focus) ==
                     GTK_WIDGET (window));
 
   if (window->primary_focus_widget)