Error notices - undefined property

I'm getting an error:

notice: Undefined property: stdClass::$display_handler in /var/www/virtual/drupal-6.x-dev/sites/all/modules/contextual/contextual.module on line 127

And some subsequent follow-on errors. It's probably to do with the dev version of Views 3 that I'm using.

Line 127 reads:
if ($display_id = $object->display_handler->display->id) {

My fix is:
if (isset($object->display_handler) && ($display_id = $object->display_handler->display->id)) {

And that works nicely.