I was using 0.9.5 with IntelliJ and when I stopped the gradle task via the IDE it worked. I upgraded to 0.9.6 today and noticed that I couldn't kill the app via the IDE. Not sure if this is a bug, or maybe I'm missing I configuration option?
Create a new ratpack project. Import to IntelliJ. Select View->Tool Windows->Gradle->run
The project starts. Stop the project in intellij; and run again. It won't start-up this time because it didn't kill the previous process even though it would appear it did so. If you do _ps ax | grep ratpack_ you'll see that the process is still running.