CellWidgets does not scroll in QTableVidget with stylesheet

The sample application (code below) does not scroll the items in the table - but if the background-color stylesheet property is not used, then everything works fine.
This happens only on OSX, the same code on Windows works correctly

#include <QApplication>
#include <QPushButton>
#include <QTableWidget>

int main(int argc, char *argv[]) {
QApplication app(argc, argv);

QTableWidget *testtable = new QTableWidget();

testtable->setRowCount(100);
testtable->setColumnCount(1);
testtable->setStyleSheet("QTableWidget

{ background-color: red; }

");
for(int i = 0 ; i < 100 ; i ++)

{ testtable->setCellWidget( i, 0, new QPushButton( QString("TEST ") + QString().setNum(i+1) ) ); }

testtable->show();
return app.exec();
return EXIT_SUCCESS;
}