Choosing startup screen in Weston + Wayland

[Prisco]

Hello everyone!
Does anyone have issues with the Wayland compositor? Here I have a Linux + Weston + Wayland machine with a small integrated LCD display (800x480) and an external HDMI monitor (1920x1080).
My goal is to programmatically select the screen on which showing a QFrame, but no matter what I do it appears on the main display. Here's an example of my attempts:

//Start application on selected screen
bool Manager::StartOnScreen(int screenIdx)
{
    _desktopWidget = QApplication::desktop();

    //Check if requested screen is available
    if(screenIdx >= _desktopWidget->screenCount())
    {
        qDebug() << "Screen index out of range";
        return false;
    }

    QWidget* screen = _desktopWidget->screen(screenIdx);
    QFrame* mainFrame = new QFrame();

    //Set frame color
    if(screenIdx == 0)
        mainFrame->setStyleSheet("background-color:rgb(0, 0, 254);");
    else
        mainFrame->setStyleSheet("background-color:rgb(254, 0, 0);");

    int width = screen->geometry().width();
    int height = screen->geometry().height();
    int x = screen->geometry().x();
    int y = screen->geometry().y();

    qDebug() << "Screen config #" + QString::number(screenIdx) + ": position=" + QString::number(x) + "x" + QString::number(y) + " size=" +QString::number(width) + "x" + QString::number(height);

    //Set frame screen and geometry
    mainFrame->setGeometry(screen->geometry());

    //Show the frame (windowed)
    mainFrame->show();

    //Show the frame (fullscreen)
    //mainFrame->showFullScreen();

    //Try to move the frame with setScreen
    //mainFrame->windowHandle()->setScreen(qApp->screens().at(screenIdx));

    return true;
}