It's a little sad right now that the only way to add something to your playlist is by pressing the play-button on the audio track. By that the audio file is being added to the current playlist and played right away.
I often want to select the music for the next 2 hours and while doing so listen to the first few selected songs, just like when using enqueue as default option on xmms/winamp... Additionally it's kind of confusing, that this is the way to build a playlist in the first place...
EDIT: Just found out that when playing audio-files, the view does not behave the way, others do, when it comes to scrolling up/down or page-up page-down... that can only be done manually with the curser-keys...

just my 2 cents... If i had the time and the knowledge of LMCE i'd do it myself... But for now I can only make a suggestion... :-/