have you looked through the settings of your Library Tree component?
i use Filters, and i can right-click tracks and send them to the end of the active playlist.
you can also drag/drop tracks and drop them into a playlist.
or right-click, choose 'send to playlist'
there are any number of ways to do this...
also see this component:
http://members.multimania.co.uk/musi...nd_to_playlist
or this:
http://www.hydrogenaudio.org/forums/...hp/t18276.html