Starting in 3.0.0 can't play multiple videos in sync using --input-slave

Before 3.0.0 using a command line like

vlc.exe video1.mkv --input-slave=video1.mkv#video2.mkv#video3.mkv

One could combine multiple video files and each video stream would have its own Direct3D window so you could view and compare them, while they play in sync.

After 3.0.0 you only get one video stream playing with the normal ability to pick one of them.