Show Red parts where masked or not.

[Mrvnlng]

Hey!

in Photoshop CC2019 or even 2020 I guess, i had the button "<" on Mac to show where i already drew the mask and where i havent. With a Red layer on the picture. Is there anyone who can tell me which button they now want me to use for it? Why did they even change this. very important feature! Thank you

Marv 

[Chuck Uebele · Accepted solution]

I believe pressing the "q" key turns off and on the red quick mask overlay.