#include <QApplication>
#include <QLabel>
#include <QScrollArea>
#include <QCheckBox>
#include <QPushButton>
#include <QVBoxLayout>

int main(int argc, char *argv[])
{
	QApplication a(argc, argv);
	QWidget w;
	{
		QVBoxLayout *layout = new QVBoxLayout(&w);
		QLabel *label = new QLabel(
			"Instructions:\n"
			"1. Try to scroll the scroll area containing buttons with mouse wheel.\n"
			"2. Disable buttons clearing the check box right below and try to scroll again. "
			"When cursor happens to be inside a disabled button it won't scroll with mouse wheel. "
			"(That is because there is unnecessary QEvent::Wheel case in the switch in QAbstractButton::event() function.)"
			, &w);
		label->setWordWrap(true);
		layout->addWidget(label);
		QCheckBox *checkBox = new QCheckBox("enable buttons", &w);
		checkBox->setChecked(true);
		layout->addWidget(checkBox);
		QScrollArea *scrollArea = new QScrollArea(&w);
		layout->addWidget(scrollArea);
		QWidget *contents = new QWidget(scrollArea);
		scrollArea->setWidget(contents);
		scrollArea->setWidgetResizable(true);
		layout = new QVBoxLayout(contents);
		const int n = 10;
		for (int i = 0; i<n; ++i)
		{
			QPushButton *button = new QPushButton("Push Button", contents);
			QObject::connect(checkBox, SIGNAL(toggled(bool)), button, SLOT(setEnabled(bool)));
			layout->addWidget(button);
		}
		contents->updateGeometry();
	}
	w.resize(240, 320);
	w.show();
	a.exec();
}