[gtk+] demos: Set crossing events mask explicitly on event-axes demo.

[Carlos Garnacho <carlosg src gnome org>]

commit b465ede53bbc3f3806117f22d53bfd634bf8d98a
Author: Carlos Garnacho <carlosg gnome org>
Date:   Thu Jun 18 15:08:39 2015 +0200

    demos: Set crossing events mask explicitly on event-axes demo.

 demos/gtk-demo/event_axes.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/demos/gtk-demo/event_axes.c b/demos/gtk-demo/event_axes.c
index 1e85ae2..c2e0b42 100644
--- a/demos/gtk-demo/event_axes.c
+++ b/demos/gtk-demo/event_axes.c
@@ -413,6 +413,8 @@ do_event_axes (GtkWidget *toplevel)
                             GDK_BUTTON_PRESS_MASK |
                             GDK_BUTTON_RELEASE_MASK |
                             GDK_SMOOTH_SCROLL_MASK |
+                            GDK_ENTER_NOTIFY_MASK |
+                            GDK_LEAVE_NOTIFY_MASK |
                             GDK_TOUCH_MASK);
 
       event_data = event_data_new ();