Maybe "too much information" here, but this is how it went:
I had not been using VLC, it was closed and the icon was inactive, as expected, in my Taskbar.
Doing something unrelated, I noticed a fleeting popup of a black cmd box... raised my eyebrows and carried on with what I was doing.
Maybe half an hour later I opened VLC and got such a shock - it was huge! I have a 3840x2160 display, and in order to read VLC's tiny font and icons I normally have to set the Compatibility to override etc etc... so I changed that setting back to default, but VLC is still huge.
This is what it looks like on full screen:
.
It's wonderful to have such a clear interface, but 2 things:
(1) I have never downloaded 3.0.4, the last update I did was 3.0.3. It has never updated itself before, tho it has told me there is an update available and I can choose whether to install it or not. I'm not complaining, just flagging the change in behaviour.
(2) My only problem with the current version is that I cannot shrink it to fit into a corner so that I can carry on with work while monitoring a webcam in VLC.
I can reduce the depth to nothing:
But the width can't be reduced any narrower than in the above snaps.
Yours gratefully