Previews of curves, brightness and contrast are missing

[luciSedova]

Hello, I have a problem with eh "previews?" of curve, level, brightness and contrast. If I want to add curve to my photo, the preview is really bad. I'll add video, because I don't know how to explain that. Any advices? I use Photoshop for almost 1 year and I haven't had any problems. 

Thank you for all advices, I feel bad about it, because I like curves.

[italosan]

Hi, what version of Adobe Photoshop are you using? What are the characteristics of your computer? Have you checked if there are updates available for your graphics card?

[luciSedova]

I use Adobe Photoshop 2020 21.1.1, Macbook Pro (macOS Mojave). Where can I checked these updates?

[italosan]

You can go to system preferences and then on system update. You will surely find the update for Mac OS Catalina.

[Chuck Uebele]

Have you tried checking  "Use Legacy Compositing" in the preferences under performance?