[gtk+/gtk-3-10] clipboard: Don't crash when data is requested from NULL window

[Benjamin Otte <otte src gnome org>]

commit c7c4b0c5fddb6b9d1e4c79c18f5b2a2c82e0bb77
Author: Benjamin Otte <otte redhat com>
Date:   Fri Dec 13 16:22:04 2013 +0100

    clipboard: Don't crash when data is requested from NULL window
    
    This could happen if data was requested from a separate screen now that
    multi-screen is no longer supported.
    
    Ideally, we'd want to support copying to other screens, but that
    requires solving in GDK as that's X-specific so cannot be well
    abstracted by GDK (without the reintroduction of multiple screens).
    
    https://bugzilla.gnome.org/show_bug.cgi?id=719314

 gtk/gtkselection.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkselection.c b/gtk/gtkselection.c
index 84bba6d..1c77002 100644
--- a/gtk/gtkselection.c
+++ b/gtk/gtkselection.c
@@ -2293,6 +2293,9 @@ _gtk_selection_request (GtkWidget *widget,
   int i;
   gulong selection_max_size;
 
+  if (event->requestor == NULL)
+    return;
+
   if (initialize)
     gtk_selection_init ();