Enqueue files and playlists to play queue

[Schnitzler 2]

Hi everbody!

I'm still fairly new to Emby, so I might have missed this, but it seems to me that one cannot add a folder or a playlist to the play queue.
My use case would be this: I am currently playing an album and would like to add another folder of music to the current playlist to shuffle through all the songs.
While I can see the 'Add to Collection' and 'Add to Playlist' for the folder, there is no option to 'Add to Play Queue'.

The same is true if I browse to an album in folder view. Adding the album to the current play queue is not offered as an option. When I search for the same album in 'Albums', the option is there.

Is this by design? Is there a way to, like, add two different playlists to the play queue?