Most of the properties are identical to the movie properties - see this page.
Movies - opens a window where you can add movies to the playlist or remove them.
Seamless - enables the "seamless connection" between the movies of the playlist, giving smoother transitions between the videos. The audio and video tracks have to have exactly the same length.
Seamless angle change - enables seamless angle changes if the playlist has angles. This is not recommended and may
not play on some players.
To use it, all movies of the playlist have to have the same number of streams.
If it is enabled, the same audio and subtitles are used for all angles. It is incompatible with PIP and 3D.
Browsable audio - here you can specify an audio file. If one is specified, the playlist becomes a browsable slideshow and the videos of all its movies are marked as browsable. The movies of a browsable slideshow must not have audio or subtitles, and angles cannot be used.