In project explorer, "tests > hu.bme.inf.symod..... > TesterAPI.java > TesterAPI > pushStart():void" shows an error. It does not affect simulation, but messages pop-up saying "Error exists in required project(s): hu.bme.inf.symod...... Proceed to Lauch?"
Also, may not be related, but in definition section (left side tab containing Buttons and interfaces) there is always a "no viable alternative at input " on the last line (even if it was a comment).
Screenshot of error