Select and Mask not working correctly in Photoshop 2021
I'm having an issue where the Select and Mask option isn't doing anyting when I adjust the sliders. It was wotking in the previous version of Photoshop just fine, but as I recently upgraded to 2021 it's stopped.
The exact problem is that unless I have Select and Mask on the Black and White preview, none of the sliders do anything at all, in any preview. But they do work in Black and White, and will take effect when I OK the dialog.
If I choose to refine the edge by using the legacy tool by holding shift and selecting form the menu, then everything works fine. It's only the new version of the tool that's stopped working.
I'm on a 2010 Mac Pro, with an 8GB Metal grahics card, 64GB of RAM, a dedicatred scratch disk and Mojave. Both the OS and Photoshop are on the latest release.