My set up is:
IntelliJ Idea 14.1.3
JetBrains IDE Support 2.0.8
I'm trying to debug the client side of a Grails application in IDEA. Since I need the compiled GWT code to load from the web-app directory of the grails app I set the -war option on the Dev mode parameters dialog to point to a sub-directory (which doesn't seem to do anything in the IntelliJ context). I also have a artifact to copy the results of the complie to the grails project web-app directory. I start grails using Tools->Grails-Run target->run-app. Then I run the debug GWT configuration to start the GWT code server. Evenything seems to work just fine. The browser window comes up with the yellow JetBrains banner, the consoles show the codeserver starting and IDEA says it's connected to Chrome. The gray panel comes over the browser window while the code compiles, then the application starts running in the browser. Everything looks great.
But, as the application runs it does not stop at any breakpoints set in the client code in IDEA.
I can post more details, but at this point I'm not sure what would be helpful.