I have troubles, and it may be because there is no validation button in the SelectColor window.
Also, note the SelectColor window width is extremely thin at first open; once I clicked on the RGB/TSL/etc. button, it enlarge itself; but no button to validate the selected color.
No crash, the change is not validated.
I wasted time yesterday with that, until I fired my other laptop with High Sierra and remove some other bugs (once there is a bug, I usually discover plenty… and in this case, I also discovers a bug in the my feature implementation (1) ).
(1) Copy / Paste, sometimes, is a plain foe.
2021r2 / last Big Sur / M1