nah.. he's talking about 'currently playing tracks'. sort of, single playlist for tracks and then library for browsing... at least i think he means that and i don't have a solution
you can set something like this up with a component called EsPlaylist. it can be configured as a library browser and in the options, you can set it when you double click an album (or any group you set yourself) it sends all the songs to a reserved playlist and starts playing from the first track. it does require a little tinkering in the preferences.example screenshot grouped by artistcomponent download: http://foo2k.chottu.net/#esp
THIS. Basically, the library shows ALL the songs, sorted by albums/artists. Then I would just choose from the library what songs I want to play, then show it on the currently playing songs, in which those chosen songs are not stored as playlists or whatsoever. Like in the late versions of WMP.