It
does continue to play if you've started playing in Party Shuffle.
I also just tried playing a playlist, and I could then go off and browse my library and edit other songs and the playlist continued playing from song to song - even though the playlist was no longer selected.
Anyway, I do know what you're getting at here and I think you're right that this might be a difference between WMP and iTunes. However maybe experiment a bit more - try using playlists and maybe Party Shuffle as your "Now Playing" list.
And so to bed
OK, here's what I did. First, I tried selecting the "Abbey Road" album by highlighting the songs, right-clicking to "Add to Party Shuffle", but it wasn't a choice, since none of the songs were checked. First conclusion: Party Shuffle only works if everything is checked.
Next, I checked everything in my library, selected "Abbey Road", right-clicked and chose "Add to Party Shuffle". Then I clicked on "Party Shuffle" on the list of playlists, then I clicked the Play button and it started. While it was playing, I then clicked "Music" in the top left panel to browse my whole library. I then typed "Santana" in the search field, which displayed only Santana songs. When the song playing in "Abbey Road" finished, it started playing a song by Dean Martin, which was neither in the Party Shuffle listing, nor in the search I had just done. (As far as I can recall, Dino never performed with the Beatles or with Santana!)
Next, I went to the Party Shuffle, highlighted all the songs, right-click, "Delete".... and the PS list repopulated with random songs from my library! Each time I would delete them to empty the PS playlist, it would repopulate with random songs. Obviously, not what I expected or wanted. I had previously disabled Party Shuffle, and now I know why!
So I'm back to my original assumption: It's much simpler to just highlight what I want to play, check the items and play. I can then check and uncheck songs at will, to add or subtract from the currently playing songs. If a song isn't checked, it won't play, unless I intentionally double-click on that song.
I don't have the hassle of creating, managing, deleting playlists, unless I want to preserve a particular group of songs to play in the future. This seems to be the easiest method, so far.