(gdb) backtrace 
#0  0x00007ffff0ec3673 in SoAction::traverse(SoNode*) () from /usr/lib/libCoin.so.60
#1  0x00007ffff0fd3677 in SoChildList::traverse(SoAction*, int, int) () from /usr/lib/libCoin.so.60
#2  0x00007ffff109687b in SoGroup::doAction(SoAction*) () from /usr/lib/libCoin.so.60
#3  0x00007ffff10aef4f in SoSeparator::doAction(SoAction*) () from /usr/lib/libCoin.so.60
#4  0x00007ffff7785f4d in Gui::SoFCUnifiedSelection::handleEvent(SoHandleEventAction*) () from /usr/lib/freecad-git/lib/libFreeCADGui.so.2
#5  0x00007ffff0ec36b4 in SoAction::traverse(SoNode*) () from /usr/lib/libCoin.so.60
#6  0x00007ffff0fd3677 in SoChildList::traverse(SoAction*, int, int) () from /usr/lib/libCoin.so.60
#7  0x00007ffff109687b in SoGroup::doAction(SoAction*) () from /usr/lib/libCoin.so.60
#8  0x00007ffff10aef4f in SoSeparator::doAction(SoAction*) () from /usr/lib/libCoin.so.60
#9  0x00007ffff0ec36b4 in SoAction::traverse(SoNode*) () from /usr/lib/libCoin.so.60
#10 0x00007ffff0fd3677 in SoChildList::traverse(SoAction*, int, int) () from /usr/lib/libCoin.so.60
#11 0x00007ffff109687b in SoGroup::doAction(SoAction*) () from /usr/lib/libCoin.so.60
#12 0x00007ffff10aef4f in SoSeparator::doAction(SoAction*) () from /usr/lib/libCoin.so.60
#13 0x00007ffff0ec36b4 in SoAction::traverse(SoNode*) () from /usr/lib/libCoin.so.60
#14 0x00007ffff0ecc618 in SoHandleEventAction::beginTraversal(SoNode*) () from /usr/lib/libCoin.so.60
#15 0x00007ffff0ec4209 in SoAction::apply(SoNode*) () from /usr/lib/libCoin.so.60
#16 0x00007ffff105d080 in SoEventManager::actuallyProcessEvent(SoEvent const*) () from /usr/lib/libCoin.so.60
#17 0x00007ffff1db5b8c in SoQtRenderArea::processSoEvent(SoEvent const*) () from /usr/lib/libSoQt.so.20
#18 0x00007ffff1dda89b in SoQtViewer::processSoEvent(SoEvent const*) () from /usr/lib/libSoQt.so.20
#19 0x00007ffff7627952 in Gui::CADNavigationStyle::processSoEvent(SoEvent const*) () from /usr/lib/freecad-git/lib/libFreeCADGui.so.2
#20 0x00007ffff7715c05 in Gui::NavigationStyle::processEvent(SoEvent const*) () from /usr/lib/freecad-git/lib/libFreeCADGui.so.2
#21 0x00007ffff77c0044 in Gui::View3DInventorViewer::processSoEvent(SoEvent const*) () from /usr/lib/freecad-git/lib/libFreeCADGui.so.2
#22 0x00007ffff1db60d0 in SoQtRenderArea::processEvent(QEvent*) () from /usr/lib/libSoQt.so.20
#23 0x00007ffff77c2171 in Gui::View3DInventorViewer::processEvent(QEvent*) () from /usr/lib/freecad-git/lib/libFreeCADGui.so.2
#24 0x00007ffff1db2dd5 in SoQtGLWidgetP::eventFilter(QObject*, QEvent*) () from /usr/lib/libSoQt.so.20
#25 0x00007ffff5aca736 in QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#26 0x00007ffff66a905c in QApplicationPrivate::notify_helper(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#27 0x00007ffff66add6b in QApplication::notify(QObject*, QEvent*) () from /usr/lib/libQtGui.so.4
#28 0x00007ffff761664f in Gui::GUIApplication::notify(QObject*, QEvent*) () from /usr/lib/freecad-git/lib/libFreeCADGui.so.2
#29 0x00007ffff5aca5ce in QCoreApplication::notifyInternal(QObject*, QEvent*) () from /usr/lib/libQtCore.so.4
#30 0x00007ffff66a9ecb in QApplicationPrivate::sendMouseEvent(QWidget*, QMouseEvent*, QWidget*, QWidget*, QWidget**, QPointer<QWidget>&, bool) () from /usr/lib/libQtGui.so.4
#31 0x00007ffff6724994 in ?? () from /usr/lib/libQtGui.so.4
#32 0x00007ffff6723721 in QApplication::x11ProcessEvent(_XEvent*) () from /usr/lib/libQtGui.so.4
#33 0x00007ffff67498b2 in ?? () from /usr/lib/libQtGui.so.4
#34 0x00007fffee32e845 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#35 0x00007fffee32eb78 in ?? () from /usr/lib/libglib-2.0.so.0
#36 0x00007fffee32ec34 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#37 0x00007ffff5af8736 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#38 0x00007ffff674952e in ?? () from /usr/lib/libQtGui.so.4
#39 0x00007ffff5ac931f in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#40 0x00007ffff5ac95a8 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#41 0x00007ffff5ace248 in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4
#42 0x00007ffff7613cdb in Gui::Application::runApplication() () from /usr/lib/freecad-git/lib/libFreeCADGui.so.2
#43 0x0000000000404003 in ?? ()
#44 0x00007ffff4adf725 in __libc_start_main () from /usr/lib/libc.so.6
#45 0x0000000000405241 in ?? ()