crash by moving window object

[MIngB]

Hi,
I did some experiments regarding my last post... many thanks for your explanations!
But now I got a case of repeatable crash, just by moving the door at attached file.
The important setting to cause this crash is the formula in Door.Width referring a spreadsheet.
Removing this formula makes everything work again.
Because I'm not sure if to post a bug report I'm asking here at first.

Freecad version 0.17R9826
gdb trace:
#0 0xb74b2e23 in App::PropertyExpressionEngine::depsAreTouched() const () from /usr/lib/libFreeCADApp.so
#1 0xb73cd0b6 in App::Document::recompute() () from /usr/lib/libFreeCADApp.so
#2 0xb79886e2 in Gui::PropertyEditor::PropertyEditor::closeEditor(QWidget*, QAbstractItemDelegate::EndEditHint) () from /usr/lib/libFreeCADGui.so
#3 0xb6b347e6 in ?? () from /usr/lib/qt4/libQtGui.so.4
#4 0xb632e4c6 in QMetaObject::activate(QObject*, QMetaObject const*, int, void**) () from /usr/lib/qt4/libQtCore.so.4
#5 0xb6cb9391 in QAbstractItemDelegate::closeEditor(QWidget*, QAbstractItemDelegate::EndEditHint) () from /usr/lib/qt4/libQtGui.so.4
#6 0xb6b8a73f in ?? () from /usr/lib/qt4/libQtGui.so.4
#7 0xb632a8ea in QMetaCallEvent::placeMetaCall(QObject*) () from /usr/lib/qt4/libQtCore.so.4
#8 0xb6332da9 in QObject::event(QEvent*) () from /usr/lib/qt4/libQtCore.so.4
#9 0xb65d3cca in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/qt4/libQtGui.so.4
#10 0xb65dab20 in QApplication::notify(QObject*, QEvent*) () from /usr/lib/qt4/libQtGui.so.4
#11 0xb77f2183 in Gui::GUIApplication::notify(QObject*, QEvent*) () from /usr/lib/libFreeCADGui.so
#12 0xb63186ea in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/qt4/libQtCore.so.4
#13 0xb631bdc1 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) () from /usr/lib/qt4/libQtCore.so.4
#14 0xb631c315 in QCoreApplication::sendPostedEvents(QObject*, int) () from /usr/lib/qt4/libQtCore.so.4
#15 0xb634a191 in ?? () from /usr/lib/qt4/libQtCore.so.4
#16 0xb33b1e24 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#17 0xb33b2149 in ?? () from /usr/lib/libglib-2.0.so.0
#18 0xb33b2216 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#19 0xb634a2f3 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/qt4/libQtCore.so.4
#20 0xb6684ac6 in ?? () from /usr/lib/qt4/libQtGui.so.4
#21 0xb631707f in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/qt4/libQtCore.so.4
#22 0xb631740e in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/qt4/libQtCore.so.4
#23 0xb631d096 in QCoreApplication::exec() () from /usr/lib/qt4/libQtCore.so.4
#24 0xb65d1f14 in QApplication::exec() () from /usr/lib/qt4/libQtGui.so.4
#25 0xb77a93d5 in Gui::Application::runApplication() () from /usr/lib/libFreeCADGui.so
#26 0x0804a95e in main ()