I use ubuntu Mate 18.04, kernel 5.0.0-32, VLC 3.0.8 Vetinari.
I have a projector connected like secondary monitor on HDMI.
I wish to start videos on HDMI display (HDMI-1), but to use control interface on primary display (eDP1). In "preferences - interface" I uncheck the box "video included in the interface" (I'm translating from Italian, I hope you'll understand), then in "video" I change "Full screen device" to HDMI-1 (is in the curtain menu).
When I start the video I obtain a window separated from the interface, full screen or not it depends if I check or uncheck the related box in video preferences, but the window with the video stay on the primary monitor (eDP1), never goes to HDMI-1.
What's wrong in my settings?