@SGaist Yes I did but the modelTest creates its own category > Q_LOGGING_CATEGORY(lcModelTest, "qt.modeltest") and I have no idea how to enable it or what. I have installed my own qInstallMessageHandler() and made sure that default() always prints whatever gets sent to it. But it looks like nothing get sends to it at all. Ok looks like I need to run this : QLoggingCategory::setFilterRules("qt.modeltest.debug=true\n");//qt.modeltest