This problem still occurs into v.2.3.3.
I have two CSS code: 1) direct into element, 2) into class .kierunki-szukaj-checkbox
When I switch editor view to media breakpoint (no matter: tablet, mobile), and then back to desktop view, and click into Custom CSS field, in this moment editor change %root% element to the element ID or class name (if I edit .kierunki-szukaj-checkbox class).
