qt5.3 tableview minimum size not work - qt

Question

i want to create calendar widget use qtableview. i test successful on Qt5.4, but on Qt5.3, the qtableview minimum size not work.
i wanto to set fixed size 300 * 300
Qt5.4 is perfect,but in Qt5.3 tableview cant show completely: http://i.stack.imgur.com/VzSjR.png
same code, same fixed size (300 * 300), but Qt5.3 cant display completely.
you can download my Demo code at: here
main.cpp:
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
MainWindow w;
w.show();
return a.exec();
}
mainwindow.cpp:
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
MyModel *model = new MyModel;
MyDelegate *delegate = new MyDelegate;
MyTableView *view = new MyTableView(this);
view->setModel(model);
view->setItemDelegate(delegate);
QHBoxLayout *layout = new QHBoxLayout;
layout->addWidget(view);
ui->widget->setLayout(layout);
ui->widget->setStyleSheet("background-color:red;");
ui->widget->setFixedSize(300, 300);
}
MainWindow::~MainWindow()
{
delete ui;
}
mydelegate.cpp:
MyDelegate::MyDelegate(QWidget *parent)
: QItemDelegate(parent)
{
}
void MyDelegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
{
painter->save();
painter->fillRect(option.rect, Qt::gray);
painter->setPen(Qt::black);
painter->drawText(option.rect, Qt::AlignCenter, index.data().toString());
painter->restore();
}
mymodel.cpp:
MyModel::MyModel()
{
}
int MyModel::rowCount(const QModelIndex &parent) const
{
Q_UNUSED(parent);
return 6;
}
int MyModel::columnCount(const QModelIndex &parent) const
{
Q_UNUSED(parent);
return 7;
}
QVariant MyModel::data(const QModelIndex &index, int role) const
{
if (role == Qt::TextAlignmentRole)
return Qt::AlignCenter;
if (role == Qt::DisplayRole)
return QString::number(index.row()) + " - " + QString::number(index.column());
return QVariant();
}
mytableview.cpp:
MyTableView::MyTableView(QWidget *parent)
: QTableView(parent)
{
setTabKeyNavigation(false);
setShowGrid(false);
verticalHeader()->setVisible(false);
horizontalHeader()->setVisible(true);
setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
setSelectionBehavior(QAbstractItemView::SelectItems);
setSelectionMode(SingleSelection);
setFrameStyle(QFrame::NoFrame);
horizontalHeader()->setSectionResizeMode(QHeaderView::Stretch);
horizontalHeader()->setSectionsClickable(false);
verticalHeader()->setSectionResizeMode(QHeaderView::Stretch);
verticalHeader()->setSectionsClickable(false);
setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
}
thanks a lot !