Note: this does not happen with the vertical slider initially created.

This is because we use the same adjustment for all widgets. Looks like that when a widget is destroyed, some signals are still active. Might be a gtk+ bug (or feature).

gtk_range_accessible_finalize() has:

  widget = gtk_accessible_get_widget (GTK_ACCESSIBLE (object));
  if (widget)
    {
      adj = gtk_range_get_adjustment (GTK_RANGE (widget));
      if (adj)
        g_signal_handlers_disconnect_by_func (adj,
                                              gtk_range_accessible_value_changed,
                                              range);
    }

but gtk_widget_real_destroy() set the widget to NULL before unrefing the accessible:

      GtkAccessible *accessible = g_object_steal_qdata (G_OBJECT (widget), quark_accessible_object);
      
      if (accessible)
        {
          gtk_accessible_set_widget (accessible, NULL);
          g_object_unref (accessible);
        }
    }

so widget is always null when gtk_range_accessible_finalize() is called and the signals are not disconnected.

Looks like gtk_widget_real_destroy should also disconnect the signal.

Added a hack in gnumeric, so we don't crash anymore.

GtkSpinButtonAccessible also connect some signals that are never disconnected.