#include <QApplication>

#include <QFileSystemModel>
#include <QTreeView>

#include "mainwidget.h"

int main(int argc, char **argv) {
QApplication app(argc, argv);

QFileSystemModel fsm;
fsm.setRootPath("/home");

QTreeView tree;
tree.setModel(&fsm);
tree.show();

return app.exec();
}

Result : The model is not rooted at '/home', but at the imaginary item above '/'