Since we override the property, we have to call the internal helper
manually.
#include "gtkboxprivate.h"
#include "gtkintl.h"
#include "gtkorientable.h"
+#include "gtkorientableprivate.h"
#include "gtkprivate.h"
#include "gtktypebuiltins.h"
#include "gtksizerequest.h"
{
case PROP_ORIENTATION:
private->orientation = g_value_get_enum (value);
+ _gtk_orientable_set_style_classes (GTK_ORIENTABLE (box));
gtk_widget_queue_resize (GTK_WIDGET (box));
break;
case PROP_SPACING: