I just updated to 6.x-1.x-dev. Now primary menu has a drop down menu with at least 3 levels, but in level 3 I can no longer select the parent item in level 2.

similar to http://drupal.org/node/564604, but not the same

if you like it more schematically:
1
-1.1
--1.1.1

if 1.1.1 exists I nothing happens when I click on 1.1

PS: I have DHTML_menu installed. I am not sure if my issue is related to this.