hi, i have create sample application , i use QTCreator, it work, the application is show in my board but when i click on button there are nothing, application don't quit. #include <QApplication> #include <QFont> #include <QPushButton> #include <QWidget> class MyWidget : public QWidget { public: MyWidget(QWidget *parent = 0); }; MyWidget::MyWidget(QWidget *parent) : QWidget(parent) { setFixedSize(200, 120); QPushButton *quit = new QPushButton(tr("Quit"), this); quit->setGeometry(62, 40, 75, 30); quit->setFont(QFont("Times", 18, QFont::Bold)); connect(quit, SIGNAL(clicked()), qApp, SLOT(quit())); } int main(int argc, char *argv[]) { QApplication app(argc, argv); MyWidget widget; widget.show(); return app.exec(); } regards, andromeda