Every time I try to add a class from the Element Properties panel PG crashes. Creating classes from the Styles panel works fine.
I’m on an iMac with the Apple M1 chip and everything up to date, with macOS Monterrey and Pinegrow 6.7 installed, but the same happened on Big Sur and an older version of Pinegrow (don’t know which actually because I installed test version first and then bought license).