How to resize Window to content?

[deleted385]

In the BarView, subclass of QGraphicsView, I've this slot:

void BarView::onShowPopup(BarSeries &s, QPointF p){
    popup->setGeometry(p.x() + 10, p.y() + 10, 0, 0);
    popup->setData(s);
    popup->show();
}

I don't give popup any width and height here. Popup has these:

Popup::Popup(QWidget *parent) : QWidget(parent){
    setWindowFlags(Qt::FramelessWindowHint | Qt::SubWindow);
    setPalette(Qt::darkGray);
    auto lay = new QVBoxLayout(this);
    setLayout(lay);
    table = new QTableView(this);
    model = new QStandardItemModel(table);
    model->setColumnCount(3);
    table->setModel(model);
    table->horizontalHeader()->hide();
    table->verticalHeader()->hide();
    table->setSizePolicy(QSizePolicy::Maximum, QSizePolicy::Maximum);
    lay->addWidget(table);
    setSizePolicy(QSizePolicy::Maximum, QSizePolicy::Maximum);
}
void Popup::setData(BarSeries &s){
    model->clear();
    auto name = new QStandardItem(s.name);
    auto val1 = new QStandardItem(QString::number(s.value1));
    auto val2 = new QStandardItem(QString::number(s.value2));
    model->appendRow(QList<QStandardItem*>() << name << val1 << val2);
    table->resizeRowsToContents();
    table->resizeColumnsToContents();
    table->adjustSize();
    adjustSize();
}

this is how it looks:

I've tried those resize/size policy/adjust BUT doesn't work! It always gets a fixed size! How to resize it to content size? One more question, I've setPalette(Qt::darkGray) in the Popup, from where does the table get black background? I want that to have the Popup background.