void QApplication::setActiveWindow(QWidget* act)
{
    QWidget* window = act?act->window():0;

    if (QApplicationPrivate::active_window == window)
        return;

#ifndef QT_NO_GRAPHICSVIEW
    if (window && window->graphicsProxyWidget()) {
        // Activate the proxy's view->viewport() ?
        return;
    }
#endif

    QWidgetList toBeActivated;
    QWidgetList toBeDeactivated;

    if (QApplicationPrivate::active_window) {
        if (style()->styleHint(QStyle::SH_Widget_ShareActivation, 0, QApplicationPrivate::active_window)) {
            QWidgetList list = topLevelWidgets();
            for (int i = 0; i < list.size(); ++i) {
                QWidget *w = list.at(i);
                if (w->isVisible() && w->isActiveWindow())
                    toBeDeactivated.append(w);
            }
        } else {
            toBeDeactivated.append(QApplicationPrivate::active_window);
        }
    }

    if (QApplicationPrivate::focus_widget) {
        if (QApplicationPrivate::focus_widget->testAttribute(Qt::WA_InputMethodEnabled))
            QGuiApplication::inputMethod()->commit();

        QFocusEvent focusAboutToChange(QEvent::FocusAboutToChange, Qt::ActiveWindowFocusReason);
        QApplication::sendEvent(QApplicationPrivate::focus_widget, &focusAboutToChange);
    }

    QApplicationPrivate::active_window = window;

    if (QApplicationPrivate::active_window) {
        if (style()->styleHint(QStyle::SH_Widget_ShareActivation, 0, QApplicationPrivate::active_window)) {
            QWidgetList list = topLevelWidgets();
            for (int i = 0; i < list.size(); ++i) {
                QWidget *w = list.at(i);
                if (w->isVisible() && w->isActiveWindow())
                    toBeActivated.append(w);
            }
        } else {
            toBeActivated.append(QApplicationPrivate::active_window);
        }

    }

    // first the activation/deactivation events
    QEvent activationChange(QEvent::ActivationChange);
    QEvent windowActivate(QEvent::WindowActivate);
    QEvent windowDeactivate(QEvent::WindowDeactivate);

    for (int i = 0; i < toBeActivated.size(); ++i) {
        QWidget *w = toBeActivated.at(i);
        sendSpontaneousEvent(w, &windowActivate);
        sendSpontaneousEvent(w, &activationChange);
    }

    for(int i = 0; i < toBeDeactivated.size(); ++i) {
        QWidget *w = toBeDeactivated.at(i);
        sendSpontaneousEvent(w, &windowDeactivate);
        sendSpontaneousEvent(w, &activationChange);
    }

    if (QApplicationPrivate::popupWidgets == 0) { // !inPopupMode()
        // then focus events
        if (!QApplicationPrivate::active_window && QApplicationPrivate::focus_widget) {
            QApplicationPrivate::setFocusWidget(0, Qt::ActiveWindowFocusReason);
        } else if (QApplicationPrivate::active_window) {
            QWidget *w = QApplicationPrivate::active_window->focusWidget();
            if (w && w->isVisible() /*&& w->focusPolicy() != QWidget::NoFocus*/)
                w->setFocus(Qt::ActiveWindowFocusReason);
            else {
                w = QApplicationPrivate::focusNextPrevChild_helper(QApplicationPrivate::active_window, true);
                if (w) {
                    w->setFocus(Qt::ActiveWindowFocusReason);
                } else {
                    // If the focus widget is not in the activate_window, clear the focus
                    w = QApplicationPrivate::focus_widget;
                    if (!w && QApplicationPrivate::active_window->focusPolicy() != Qt::NoFocus)
                        QApplicationPrivate::setFocusWidget(QApplicationPrivate::active_window, Qt::ActiveWindowFocusReason);
                    else if (!QApplicationPrivate::active_window->isAncestorOf(w))
                        QApplicationPrivate::setFocusWidget(0, Qt::ActiveWindowFocusReason);
                }
            }
        }
    }
}