Since the 10.14.6 update there have been graphical issues when running an active window in VLC. Drop-down menus and right-clicks system wide flicker pink and are unusable.
Affecting other users as noted on VLC forum: https://forum.videolan.org/viewtopic.php?f=12&t=150323&p=494372#p494372
Flagging here, too.
iMac Line (2012 and Later)
Maybe the solution recently posted in the vlc forum will also help you: turn automatic graphics switching on is said to have helped.
I haven’t tried vlc with 10.14.6 yet, but may do so later when I’m at my mac. I also have a mac with two gpu so if this is the issue I may be able to reproduce it.
Can't reproduce the problem on Late 2015 5K iMac. What file format are you playing?
.mp4, .avi, .mkv all affected. Doesn't seem to matter. With VLC open but the active window closed things are fine. But playback renders the above unusable.
Graphical issues with VLC with 10.14.6
