On my laptop I have runing yakuake. When I plug in my external monitor and switch the main screen to it, yakuake always crashes.

This is the backtrace:

#0  QScreen::handle (this=0x0) at kernel/qscreen.cpp:93
#1  0x00007fffe65f2295 in QXcbWindow::QXcbWindow (this=0x7f3070, window=0x87c900) at qxcbwindow.cpp:252
#2  0x00007fffe65e0eb1 in QXcbIntegration::createPlatformWindow (this=<optimized out>, window=0x87c900)
    at qxcbintegration.cpp:183
#3  0x00007ffff44b5b43 in QWindow::create (this=this@entry=0x87c900) at kernel/qwindow.cpp:520
#4  0x00007ffff44b86f8 in QWindow::setVisible (this=this@entry=0x87c900, visible=visible@entry=true)
    at kernel/qwindow.cpp:455
#5  0x00007ffff791a7e6 in QWidgetPrivate::show_sys (this=this@entry=0x7194f0) at kernel/qwidget.cpp:7860
#6  0x00007ffff79219b6 in QWidgetPrivate::show_helper (this=this@entry=0x7194f0) at kernel/qwidget.cpp:7789
#7  0x00007ffff792398a in QWidget::setVisible (this=0x7fffffffd580, visible=<optimized out>) at kernel/qwidget.cpp:8088
#8  0x0000000000426cad in MainWindow::xshapeOpenWindow (this=0x7fffffffd580)
    at /var/tmp/portage/kde-misc/yakuake-9999/work/yakuake-9999/app/mainwindow.cpp:1123
#9  0x00007ffff41b1e54 in QMetaObject::activate (sender=sender@entry=0x7fffffffd618, signalOffset=<optimized out>, 
    local_signal_index=local_signal_index@entry=0, argv=argv@entry=0x0) at kernel/qobject.cpp:3709
#10 0x00007ffff41b2517 in QMetaObject::activate (sender=sender@entry=0x7fffffffd618, 
    m=m@entry=0x7ffff43c0540 <QTimer::staticMetaObject>, local_signal_index=local_signal_index@entry=0, 
    argv=argv@entry=0x0) at kernel/qobject.cpp:3575
#11 0x00007ffff4232c90 in QTimer::timeout (this=this@entry=0x7fffffffd618) at .moc/moc_qtimer.cpp:192
#12 0x00007ffff41bf762 in QTimer::timerEvent (this=0x7fffffffd618, e=<optimized out>) at kernel/qtimer.cpp:255
#13 0x00007ffff41b2b0c in QObject::event (this=0x7fffffffd618, e=<optimized out>) at kernel/qobject.cpp:1230
#14 0x00007ffff78e51ec in QApplicationPrivate::notify_helper (this=this@entry=0x6a9dc0, 
    receiver=receiver@entry=0x7fffffffd618, e=e@entry=0x7fffffffd1e0) at kernel/qapplication.cpp:3729
#15 0x00007ffff78ea1e0 in QApplication::notify (this=0x7fffffffd550, receiver=0x7fffffffd618, e=0x7fffffffd1e0)
    at kernel/qapplication.cpp:3512
#16 0x00007ffff418141d in QCoreApplication::notifyInternal (this=0x7fffffffd550, receiver=0x7fffffffd618, 
    event=event@entry=0x7fffffffd1e0) at kernel/qcoreapplication.cpp:940
#17 0x00007ffff41da21d in sendEvent (event=0x7fffffffd1e0, receiver=<optimized out>)
    at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:236
#18 QTimerInfoList::activateTimers (this=0x6dca90) at kernel/qtimerinfo_unix.cpp:643
---Type <return> to continue, or q <return> to quit---
#19 0x00007ffff41da551 in timerSourceDispatch (source=<optimized out>) at kernel/qeventdispatcher_glib.cpp:185
#20 0x00007fffeea9e984 in g_main_context_dispatch () from /usr/lib64/libglib-2.0.so.0
#21 0x00007fffeea9ebc8 in ?? () from /usr/lib64/libglib-2.0.so.0
#22 0x00007fffeea9ec6c in g_main_context_iteration () from /usr/lib64/libglib-2.0.so.0
#23 0x00007ffff41da85b in QEventDispatcherGlib::processEvents (this=0x6dcee0, flags=...)
    at kernel/qeventdispatcher_glib.cpp:428
#24 0x00007ffff417f2bb in QEventLoop::exec (this=this@entry=0x7fffffffd440, flags=..., flags@entry=...)
    at kernel/qeventloop.cpp:212
#25 0x00007ffff4186caf in QCoreApplication::exec () at kernel/qcoreapplication.cpp:1193
#26 0x00007ffff44aa13c in QGuiApplication::exec () at kernel/qguiapplication.cpp:1515
#27 0x00007ffff78e19d5 in QApplication::exec () at kernel/qapplication.cpp:2964
#28 0x000000000041ef02 in main (argc=1, argv=<optimized out>)
    at /var/tmp/portage/kde-misc/yakuake-9999/work/yakuake-9999/app/main.cpp:73

Reproducible: Always