In the new version 1.6 of Lightbox, neither of the following settings in Admin >> Zen Lightbox are functioning/controlling click behavior.

The reason for this appears to be because the new version of the slimbox.php file (\includes\classes\zen_lightbox) does not include the event handlers that are needed for these controls to function.

Close on Image Click
Close on Overlay Click

old code in slimbox.php:
<?php if (ZEN_LIGHTBOX_CLOSE_OVERLAY == 'true') { echo '.addEvent("click",C)'; } ?>
Great product 'upgrade!'