The Search... dialog for Docker Machines in the New Connection wizard in the Docker tooling does not work: a warning message appears in the Error Log view, saying :

The 'docker-machine' command could not be located in /usr/bin:/bin:/usr/sbin:/sbin

even though the preferences show that the docker-machine command is located in /usr/local/bin.

See https://bugs.eclipse.org/bugs/show_bug.cgi?id=493328