Alright, I found the reason. QWidget::create() clears the Qt::WA_QuitOnClose attribute for anything but Qt::Window, Qt::Widget or Qt::Dialog. The workaround is to call for example QWidget::show() first, and set the attribute by hand afterwards:
Qt Code:
#include <QtGui>
intmain(intargc, char*argv[])
{
QApplicationapp(argc, argv);
QMainWindowwin(0, Qt::Tool);
win.show(); // must be called before setting Qt::WA_QuitOnClose
win.setAttribute(Qt::WA_QuitOnClose);
returnapp.exec();
}