Qt: "Expanding" doesn't work inside a layout

My purpose is to create a scrollable control with a QVBoxLayout inside of it that has various controls (say buttons) on it. That control is put on a *.ui form. In the constructor for that control I write the following code: ``` MyScrollArea::MyScrollArea(QWidget *parent) : QScrollArea(parent) { // create the scrollable container this->container = new QWidget(); // container widget member this->container->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding); this->container->setContentsMargins(QMargins(0,0,0,0)); this->content = new QVBoxLayout(); // layout member this->content->setMargin(0); this->content->setSpacing(0); for (int i=0; i<100; i++) { QPushButton * widget = new QPushButton(); widget->setText("button"); widget->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed); this->content->addWidget(widget); } this->container->setLayout(this->content); this->content->layout(); this->setWidget(this->container); } ``` My problem: the buttons have a fixed size and do not expand horizontally. they have a fixed size. i'd like them to expand horizontally to fill the row they're in. How can I get them expanding horizontally across their parent container?