From b880296354e98db738fc038cbffe2c21869ffa07 Mon Sep 17 00:00:00 2001
From: Benjamin Otte <otte@redhat.com>
Date: Wed, 1 Nov 2017 18:16:11 +0100
Subject: [PATCH] window: Unset transient parent in set_display()

If somebody changes a window's display, the transient parent cannot
stay if it's on a different display.
---
 gtk/gtkwindow.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/gtk/gtkwindow.c b/gtk/gtkwindow.c
index c9716a698b..8aba4f8d52 100644
--- a/gtk/gtkwindow.c
+++ b/gtk/gtkwindow.c
@@ -9966,6 +9966,9 @@ gtk_window_set_display (GtkWindow  *window,
   if (_gtk_widget_get_realized (widget))
     gtk_widget_unrealize (widget);
 
+  if (priv->transient_parent && gtk_widget_get_display (GTK_WIDGET (priv->transient_parent)) != display)
+    gtk_window_set_transient_for (window, NULL);
+
   gtk_window_free_key_hash (window);
   priv->display = display;
 #ifdef GDK_WINDOWING_X11
-- 
2.30.2