When creating a new playlist I am only able to set name of playlist, I do not seem to find how to add songs to playlist other than going back to browse and either choosing one by one by longpressing or adding whole folder then removing songs not wanted.

Also, editing a playlist only allows to remove not add songs.

When long-clicking a song I do not see option of adding to both playlists, only one appears.
And not being able to multiselect songs to add to playlist is a hassle.

I am able to select and multiselect via context menu - by clicking settings (spanner icon), then choosing context menu current view:

But still only one playlist appears not both: