[gtk+/gtk-3-22] gtkrange: Instaurate GTK+ grabs while manipulating ranges

[Carlos Garnacho <carlosg src gnome org>]

commit 9b032073cbcf5aadbeb4b74f0cf662a9fa5f5530
Author: Carlos Garnacho <carlosg gnome org>
Date:   Mon Jun 26 19:26:26 2017 +0200

    gtkrange: Instaurate GTK+ grabs while manipulating ranges
    
    It should not be necessary for most situations, except while there's
    GDK grabs coercing events in a different way.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=782870

 gtk/gtkrange.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkrange.c b/gtk/gtkrange.c
index a7497a4..98ec13b 100644
--- a/gtk/gtkrange.c
+++ b/gtk/gtkrange.c
@@ -2426,6 +2426,8 @@ range_grab_add (GtkRange      *range,
   update_steppers_state (range);
 
   gtk_style_context_add_class (context, "dragging");
+
+  gtk_grab_add (GTK_WIDGET (range));
 }
 
 static void
@@ -2453,6 +2455,7 @@ range_grab_remove (GtkRange *range)
   if (!priv->grab_location)
     return;
 
+  gtk_grab_remove (GTK_WIDGET (range));
   context = gtk_widget_get_style_context (GTK_WIDGET (range));
 
   gtk_css_gadget_queue_allocate (priv->grab_location);