We haven't tested BC4 in a docker container. Beyond Compare for Linux still requires an X-Window session, so if your Docker container is headless and you don't have an X-Window client connected to it, Beyond Compare will not run.

Usually if you're working on a Linux system without X-Window, it's best to just install Beyond Compare on a supported operating system (Windows, Linux, macOS), then access the system via FTP, SFTP, or Samba.