Having a file open in a separate window makes the Qt Creator to crash when switching sessions

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff5b7bee6 in ?? () from /work/Qt_binaries/qt_5.5.1/Tools/QtCreator/bin/../lib/qtcreator/libQt5Core.so.5
(gdb) bt
#0  0x00007ffff5b7bee6 in ?? () from /work/Qt_binaries/qt_5.5.1/Tools/QtCreator/bin/../lib/qtcreator/libQt5Core.so.5
#1  0x00007ffff5b7c561 in QObject::disconnectImpl(QObject const*, void**, QObject const*, void**, QMetaObject const*) ()
   from /work/Qt_binaries/qt_5.5.1/Tools/QtCreator/bin/../lib/qtcreator/libQt5Core.so.5
#2  0x00007fffcf448454 in ?? () from /work/Qt_binaries/qt_5.5.1/Tools/QtCreator/lib/qtcreator/plugins/libCore.so
#3  0x00007fffcf448489 in ?? () from /work/Qt_binaries/qt_5.5.1/Tools/QtCreator/lib/qtcreator/plugins/libCore.so
#4  0x00007ffff5b79418 in QObject::event(QEvent*) ()
   from /work/Qt_binaries/qt_5.5.1/Tools/QtCreator/bin/../lib/qtcreator/libQt5Core.so.5
#5  0x00007ffff6f05377 in QWidget::event(QEvent*) ()
   from /work/Qt_binaries/qt_5.5.1/Tools/QtCreator/bin/../lib/qtcreator/libQt5Widgets.so.5
#6  0x00007ffff6ec44cc in QApplicationPrivate::notify_helper(QObject*, QEvent*) ()
   from /work/Qt_binaries/qt_5.5.1/Tools/QtCreator/bin/../lib/qtcreator/libQt5Widgets.so.5
#7  0x00007ffff6ec9630 in QApplication::notify(QObject*, QEvent*) ()
   from /work/Qt_binaries/qt_5.5.1/Tools/QtCreator/bin/../lib/qtcreator/libQt5Widgets.so.5
#8  0x00007ffff5b4a663 in QCoreApplication::notifyInternal(QObject*, QEvent*) ()
   from /work/Qt_binaries/qt_5.5.1/Tools/QtCreator/bin/../lib/qtcreator/libQt5Core.so.5
#9  0x00007ffff5b4c8d3 in QCoreApplicationPrivate::sendPostedEvents(QObject*, int, QThreadData*) ()
   from /work/Qt_binaries/qt_5.5.1/Tools/QtCreator/bin/../lib/qtcreator/libQt5Core.so.5
#10 0x00007ffff5b9f693 in ?? () from /work/Qt_binaries/qt_5.5.1/Tools/QtCreator/bin/../lib/qtcreator/libQt5Core.so.5
#11 0x00007ffff3d30e04 in g_main_dispatch (context=0x7fffe8003000) at /build/buildd/glib2.0-2.40.2/./glib/gmain.c:3064
#12 g_main_context_dispatch (context=context@entry=0x7fffe8003000) at /build/buildd/glib2.0-2.40.2/./glib/gmain.c:3663
#13 0x00007ffff3d31048 in g_main_context_iterate (context=context@entry=0x7fffe8003000, block=block@entry=1, 
    dispatch=dispatch@entry=1, self=<optimized out>) at /build/buildd/glib2.0-2.40.2/./glib/gmain.c:3734
#14 0x00007ffff3d310ec in g_main_context_iteration (context=0x7fffe8003000, may_block=1)
    at /build/buildd/glib2.0-2.40.2/./glib/gmain.c:3795
#15 0x00007ffff5b9fa87 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) ()
   from /work/Qt_binaries/qt_5.5.1/Tools/QtCreator/bin/../lib/qtcreator/libQt5Core.so.5
#16 0x00007ffff5b48212 in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) ()