I have made progress, I set the content root to ./appinventor-sources/appinventor/components/src and now I see better infos!
I still am unsure where to put my Clicks.java file in the full source code setup though. Am I doing it right so far?
EDIT: Well I put my java file there too and it all seems to be working, pretty cool.
EDIT2: Maybe you can help with the follow up question -> Help finding an external library (not adding)