I choose to open existing "file or project" - and I point it to one of my single-file python files.
now I can edit it, but not refactor, apparently because it does not belong to a project.
So I make a new empty project, this time I drag'n'drop a file into the editor (this project?) - and ...same.
Is it so, that for PyCharm to work, it needs whatever file/files ti be located inside ~/PyCharmProjects/<project> ? can't it be used as a good editor wherever the file is ?