QDialog::show() not displaying child

[Wasabi]

I've just started tinkering with QDialog and so just wanted to create one with a button saying "OK" there. The code's the following:

bool MyCanvas::HorizonDialog()
{
    QDialog* dlg = new QDialog(this);
    dlg->setAttribute(Qt::WA_DeleteOnClose);
    QHBoxLayout layout;
    QPushButton ok("OK",dlg);
    ok.setDefault(true);
    connect(&ok,SIGNAL(clicked()),dlg,SLOT(close()));
    layout.addWidget(&ok);
    dlg->setLayout(&layout);
    dlg->raise();
    dlg->show();
    return true;
}

bool MyCanvas::HorizonDialog()
{
    QDialog* dlg = new QDialog(this);
    dlg->setAttribute(Qt::WA_DeleteOnClose);
    QHBoxLayout layout;
    QPushButton ok("OK",dlg);
    ok.setDefault(true);
    connect(&ok,SIGNAL(clicked()),dlg,SLOT(close()));
    layout.addWidget(&ok);
    dlg->setLayout(&layout);
    dlg->raise();
    dlg->show();
    return true;
}

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I want the dialog to be modeless, so I chose to use QDialog::show() instead of ::exec(). However, when I run the program, the pushbutton doesn't appear. Should I use QDialog::exec(), however, the button does appear and everything works fine. I've tried "ok.show()" both before and after "dlg->show()" and neither worked.

Help?