I recently ran into problems SQL Developer 21.2.0187 running on macOS Catalina, not sure what had changed but the problems manifested as:
- Typing into SQL Worksheet was sluggish to the point of unusable, especially using the backspace.
- Within preferences it was not possible to view a number of screens such as the PL/SQL Syntax Colors options.
Fortunately following the advice in Jeff Smith’s post, shown below, fixed the issue.