[gtk+/gtk-3-22] Revert "combobox: remove superfluous GTK+ grabs"

[Daniel Boles <dboles src gnome org>]

commit 13017239055dc492f7e5cdeae63f01e6e820da4e
Author: Daniel Boles <dboles src gnome org>
Date:   Mon Aug 28 18:38:45 2017 +0100

    Revert "combobox: remove superfluous GTK+ grabs"
    
    This reverts commit 46b4e5d38877197503f802380e5c9a469218f99b.
    
    Apparently these weren’t so redundant, because their removal introduced
    at least 2 bugs in list-mode ComboBoxes: failure to close the popup upon
    clicking out of it, and failing to receive mouse input in the popup of a
    CB in a modal window. It may also have caused (even more!) stuck grabs.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=738387
    https://bugzilla.gnome.org/show_bug.cgi?id=776793

 gtk/gtkcombobox.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkcombobox.c b/gtk/gtkcombobox.c
index fa1e26c..ede2fba 100644
--- a/gtk/gtkcombobox.c
+++ b/gtk/gtkcombobox.c
@@ -2374,6 +2374,7 @@ gtk_combo_box_popup_for_device (GtkComboBox *combo_box,
       return;
     }
 
+  gtk_device_grab_add (priv->popup_window, pointer, TRUE);
   priv->grab_pointer = pointer;
 
   g_signal_connect (priv->popup_window,
@@ -2448,6 +2449,7 @@ gtk_combo_box_popdown (GtkComboBox *combo_box)
   if (priv->grab_pointer)
     gdk_seat_ungrab (gdk_device_get_seat (priv->grab_pointer));
 
+  gtk_device_grab_remove (priv->popup_window, priv->grab_pointer);
   gtk_widget_hide (priv->popup_window);
   gtk_toggle_button_set_active (GTK_TOGGLE_BUTTON (priv->button),
                                 FALSE);