This functionality is only used by the testing tool so far and currently it is not possible to define more than one root through the ecf file. However the plan is to add UI and configuration support for multiple roots in 6.4. The idea is that one can specify multiple roots and choose which one to execute when launching the application. Currently this is done by a specific command line argument which is hidden from arguments in the Eiffel application. Another possibility would be a special environment variable.