QScrollArea in a QTabWidget page

[CoderMan]

Yep, the size constraint was the solution:

//header for class holding tab widget
QGridLayout* dataLayout;
QWidget* page;
QTabWidget* tabs;
QVBoxLayout* mainLayout;
 
//constructor
dataLayout = new QGridLayout();
page = new QWidget(this);
QScrollArea* scrollArea = new QScrollArea(this);
dataLayout->setSizeConstraint(QLayout::SetFixedSize); //important!
page->setLayout(dataLayout);
scrollArea->setWidget(page);
tabs->addTab(scrollArea, tr("Some items"));
mainLayout->addWidget(tabs);
this->setLayout(mainLayout);
 
//test add after construction
for (int n = 0; n < 40; ++n)
{
  SomeItem* item = new SomeItem(this);
  item->setStuff("whatever");
  dataLayout->addWidget(item);
}

//header for class holding tab widget
QGridLayout* dataLayout;
QWidget* page;
QTabWidget* tabs;
QVBoxLayout* mainLayout;

//constructor
dataLayout = new QGridLayout();
page = new QWidget(this);
QScrollArea* scrollArea = new QScrollArea(this);
dataLayout->setSizeConstraint(QLayout::SetFixedSize); //important!
page->setLayout(dataLayout);
scrollArea->setWidget(page);
tabs->addTab(scrollArea, tr("Some items"));
mainLayout->addWidget(tabs);
this->setLayout(mainLayout);

//test add after construction
for (int n = 0; n < 40; ++n)
{
  SomeItem* item = new SomeItem(this);
  item->setStuff("whatever");
  dataLayout->addWidget(item);
}

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• Without setSizeConstraint(QLayout::SetFixedSize) the items will not even be displayed
• Adding items in the constructor does not work (tried after every phase)
• Not using a "page" QWidget and calling scrollArea->setLayout(dataLayout)
  does not work. Subclassing an actual custom Page widget from QWidget, however, is not
  required.

I wonder what use does QScrollArea::setLayout() even have?