Because of some unexplainable reason they have invented the wheel again and turned everything upside down with the checkboxes. Read about it here
http://www.liferay.com/es/community/forums/-/message_boards/message/7285601Basicly it sends each and every checkbox which has the value attributge set, and ive tried to get that thing to work for a category menu hook for a day. Have it working..almost, still having trouble with some checked inputs getting unchecked on form submit, when i intend to have them rechecked as the menu is rendered on form submit.
Ofcourse getting to find out these things takes about a days worth of backward engineering as everything is so well commented and documented