Crash in Xcb bindings (QBackingStore behind graphics view)

With the Qml Designer in Qt Creator I get the following crash sporadically.

0 __lll_lock_wait lowlevellock.S 135 0x7f50c81b282c
1 _L_lock_982 /lib/x86_64-linux-gnu/libpthread.so.0 0x7f50c81ae17c
2 _GI__pthread_mutex_lock pthread_mutex_lock.c 64 0x7f50c81adfcb
3 xcb_send_request xcb_out.c 234 0x7f50c52d3213
4 xcb_create_gc xproto.c 8322 0x7f50c52da04c
5 QXcbShmImage::put qxcbbackingstore.cpp 170 0x7f50c237df7b
6 QXcbBackingStore::flush qxcbbackingstore.cpp 316 0x7f50c237e8e4
7 QBackingStore::flush qbackingstore.cpp 113 0x7f50c8e5c3ec
8 qt_flush qwidgetbackingstore.cpp 119 0x7f50c9892828
9 QWidgetBackingStore::flush qwidgetbackingstore.cpp 1105 0x7f50c98971e3
10 QWidgetBackingStore::endPaint qwidgetbackingstore.cpp 333 0x7f50c989306b
11 QWidgetBackingStore::sync qwidgetbackingstore.cpp 1093 0x7f50c989710f
12 QWidgetPrivate::syncBackingStore qwidget.cpp 1680 0x7f50c98c1c43
13 QWidget::event qwidget.cpp 8226 0x7f50c98d2b83
14 QMainWindow::event qmainwindow.cpp 1471 0x7f50c9a48151
15 QApplicationPrivate::notify_helper qapplication.cpp 3470 0x7f50c98886b4
16 QApplication::notify qapplication.cpp 3435 0x7f50c988850f
17 QCoreApplication::notifyInternal qcoreapplication.cpp 871 0x7f50c86bfa18
18 QCoreApplication::sendEvent qcoreapplication.h 232 0x7f50c86c3683
19 QCoreApplicationPrivate::sendPostedEvents qcoreapplication.cpp 1475 0x7f50c86c0d2d
20 QCoreApplication::sendPostedEvents qcoreapplication.cpp 1333 0x7f50c86c06bf
21 QGraphicsViewPrivate::dispatchPendingUpdateRequests qgraphicsview_p.h 202 0x7f50c9c62919
22 QGraphicsScenePrivate::_q_emitUpdated qgraphicsscene.cpp 383 0x7f50c9c49546
23 QGraphicsScene::qt_static_metacall moc_qgraphicsscene.cpp 175 0x7f50c9c61da1
24 QMetaCallEvent::placeMetaCall qobject.cpp 479 0x7f50c86fb553
25 QObject::event qobject.cpp 1078 0x7f50c86fc508
26 QGraphicsScene::event qgraphicsscene.cpp 3478 0x7f50c9c54068
27 QmlDesigner::FormEditorScene::event formeditorscene.cpp 351 0x7f50944cd97e
28 QApplicationPrivate::notify_helper qapplication.cpp 3470 0x7f50c98886b4
29 QApplication::notify qapplication.cpp 2891 0x7f50c9885a41
30 QCoreApplication::notifyInternal qcoreapplication.cpp 871 0x7f50c86bfa18
31 QCoreApplication::sendEvent qcoreapplication.h 232 0x7f50c86c3683
32 QCoreApplicationPrivate::sendPostedEvents qcoreapplication.cpp 1475 0x7f50c86c0d2d
33 QCoreApplication::sendPostedEvents qcoreapplication.cpp 1333 0x7f50c86c06bf
34 postEventSourceDispatch qeventdispatcher_glib.cpp 279 0x7f50c8736cd3
35 g_main_context_dispatch /lib/x86_64-linux-gnu/libglib-2.0.so.0 0x7f50c718df05
36 ?? /lib/x86_64-linux-gnu/libglib-2.0.so.0 0x7f50c718e248
37 g_main_context_iteration /lib/x86_64-linux-gnu/libglib-2.0.so.0 0x7f50c718e304
38 QEventDispatcherGlib::processEvents qeventdispatcher_glib.cpp 426 0x7f50c87374a9
39 QPAEventDispatcherGlib::processEvents qeventdispatcher_glib.cpp 123 0x7f50c2391be6
40 QEventLoop::processEvents qeventloop.cpp 136 0x7f50c86bc62a
41 QEventLoop::exec qeventloop.cpp 212 0x7f50c86bc8ff
42 QCoreApplication::exec qcoreapplication.cpp 1124 0x7f50c86c00ed
43 QGuiApplication::exec qguiapplication.cpp 1328 0x7f50c8cb507a
44 QApplication::exec qapplication.cpp 2695 0x7f50c98852e3
45 main main.cpp 530 0x40e73f