When a widget is shown that has a QPushButton as the child with the initial focus then the focus is not drawn until it changes.

#include <QtGui>

int main(int argc, char **argv)
{
    QApplication a(argc, argv);
    QWidget w;
    QPushButton *pb = new QPushButton("Test", &w);
    QLineEdit *le = new QLineEdit(&w);
    le->move(100,100);
    w.show();
    return a.exec();
}