I did the following
- Download PHP Mess Detector Plugin
- Choose a PHP Interpreter (Languages & Frameworks -> PHP -> CLI Interpeter
- Made sure that my Mess Detector Plugin is setup is properly and has a Interpreter assigned, that has phpmd installed. (Languages & Frameworks -> PHP -> Mess Detector -> Configuration -> Click on ... -> Click on Validate
But when I go to Languages & Frameworks -> PHP -> Inspections -> PHP Mess Detector validation and try to add a Custom ruleset I get the following message:
"Custom rules are not supported for current interpreter"