Kindly contact the bitdefender support by visiting https://www.bitdefender.com/consumer/support/
Regards
Flex
(Bitdefender beta tester 2019/ 2020)
I did that already, but they have no idea... the best idea they gave me was that I should reinstall my graphics card and restart my computer. I did this and 100 other things, even trying another graphics card, and still all the fonts are white. So I'll switch to Kaspersky next year... it's the easiest solution :-/