[gtk+] scalebutton: Set GDK_SCROLL_MASK explicitly

[Matthias Clasen <matthiasc src gnome org>]

commit 377eb396a36801da32d1e1cf01560871a3c07cda
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu Feb 23 14:47:13 2012 +0100

    scalebutton: Set GDK_SCROLL_MASK explicitly
    
    selecting for button press/release doesn't suffice anymore to
    get scroll events.

 gtk/gtkscalebutton.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkscalebutton.c b/gtk/gtkscalebutton.c
index fa6c57f..b91c679 100644
--- a/gtk/gtkscalebutton.c
+++ b/gtk/gtkscalebutton.c
@@ -415,6 +415,8 @@ gtk_scale_button_init (GtkScaleButton *button)
   /* the scale */
   priv->scale = gtk_scale_button_scale_new (button);
   gtk_container_add (GTK_CONTAINER (priv->box), priv->scale);
+
+  gtk_widget_add_events (GTK_WIDGET (button), GDK_SCROLL_MASK);
 }
 
 static GObject *