[#29321] Fixed hiding items from dropdown menu in during assigning modules to pages

Fixed issue with hiding items in dropdown menu when selecting pages for modul to display and using search feature

Here is the original ticket:
http://joomlacode.org/gf/project/joomla/tracker/?action=TrackerItemEdit&tracker_item_id=29321

There is also a need to generate new file treeselectmenu.jquery.min.js, but I dont know how, so If anybody can do it or post instructions in here.