[gtk+/wip/carlosg/event-delivery: 89/119] gtkwindow: Ignore implicit grabs going away if there is no focus

[Timm Bäder <baedert src gnome org>]

commit 4052f1449475e092c5ea3b44bcc548a98b8f5802
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sat Apr 1 22:41:23 2017 +0200

    gtkwindow: Ignore implicit grabs going away if there is no focus
    
    There should be no circumstances where an implicit grab is requested but
    no focus exists, there's however circumstances (like windowing grabs taking
    input to a different window) where we might get implicit grabs being undone
    when then new window didn't create a focus for the pointer itself.

 gtk/gtkwindow.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkwindow.c b/gtk/gtkwindow.c
index 065760d..b0972a9 100644
--- a/gtk/gtkwindow.c
+++ b/gtk/gtkwindow.c
@@ -11597,6 +11597,8 @@ gtk_window_set_pointer_focus_grab (GtkWindow        *window,
   GtkPointerFocus *focus;
 
   focus = gtk_window_lookup_pointer_focus (window, device, sequence);
+  if (!focus && !grab_widget)
+    return;
   g_assert (focus != NULL);
   gtk_pointer_focus_set_implicit_grab (focus, grab_widget);
 }