PeTrack crashes when clicking on PersonNr in context menu

PeTrack crashes with a Segmentation Fault when clicking on the top button of the context menu in tracking (right click on trackpoint). The button displays: PersonNr: XX height: XX frames: [XX..XX]

with the following stack trace:

QGridLayout::addItem(QLayoutItem*, int, int, int, int, QFlags<Qt::AlignmentFlag>) 0x00007f5d24638a92
TrackerItem::contextMenuEvent trackerItem.cpp:271
QGraphicsItem::sceneEvent(QEvent*) 0x00007f5d2491d7fa
QGraphicsScene::contextMenuEvent(QGraphicsSceneContextMenuEvent*) 0x00007f5d24941b2e
QGraphicsScene::event(QEvent*) 0x00007f5d249541da
QApplicationPrivate::notify_helper(QObject*, QEvent*) 0x00007f5d2461b752
QCoreApplication::notifyInternal2(QObject*, QEvent*) 0x00007f5d23b53a7a
QGraphicsView::contextMenuEvent(QContextMenuEvent*) 0x00007f5d2497262e
QWidget::event(QEvent*) 0x00007f5d2465cb0e
QFrame::event(QEvent*) 0x00007f5d2470816f
QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) 0x00007f5d23b537e3
QApplicationPrivate::notify_helper(QObject*, QEvent*) 0x00007f5d2461b741
QApplication::notify(QObject*, QEvent*) 0x00007f5d24623525
QCoreApplication::notifyInternal2(QObject*, QEvent*) 0x00007f5d23b53a7a
<unknown> 0x00007f5d24675db1
<unknown> 0x00007f5d2467863f
QApplicationPrivate::notify_helper(QObject*, QEvent*) 0x00007f5d2461b752
QCoreApplication::notifyInternal2(QObject*, QEvent*) 0x00007f5d23b53a7a
QGuiApplicationPrivate::processMouseEvent(QWindowSystemInterfacePrivate::MouseEvent*) 0x00007f5d23f2d594
QWindowSystemInterface::sendWindowSystemEvents(QFlags<QEventLoop::ProcessEventsFlag>) 0x00007f5d23f02bb5
<unknown> 0x00007f5d12b8a16c
g_main_context_dispatch 0x00007f5d1b97da84
<unknown> 0x00007f5d1b9d19b1
g_main_context_iteration 0x00007f5d1b97c2b1
QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) 0x00007f5d23bac6e1
QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) 0x00007f5d23b523fc
QCoreApplication::exec() 0x00007f5d23b5a894
main main.cpp:225
__libc_start_main 0x00007f5d1c452152
_start 0x000055bd7d90d99e

In this part the seg fault occurs:

QSpacerItem* horizontalSpacer = new QSpacerItem(300, 0, QSizePolicy::Minimum, QSizePolicy::Expanding);
QGridLayout* layout = (QGridLayout*)msgBox.layout();
msgBox.setWindowTitle("PeTrack");
msgBox.setIcon(QMessageBox::Information);
layout->addItem(horizontalSpacer, layout->rowCount(), 0, 1, layout->columnCount());
msgBox.setStandardButtons(QMessageBox::Ok);
msgBox.setDefaultButton(QMessageBox::Ok);
msgBox.setEscapeButton(QMessageBox::Ok);
msgBox.exec();

Additional information: