Multi Tab

...hello there just wanted to ask for opinion...
...problem started from today... there was some kind of win 10 pro update after which i can no longer start like 2 sessions ( of same wow ) at the same time... its not about my build that's for sure... so basically i used to run 4-5 accounts simultaneously... but from today when i open 1 and then get to win, open another, it opens the wow there is sound but screen is like 100% transparent... and so on for 3rd 4th etc ...

P.S. just found out that problem persist only if there is fullscreen option turned on... in window mode everything is alright!!!