can't reproduce here

can reproduce here, stack slighly more complete but still not 100% ok

Thread 1 (Thread 0xafa6e980 (LWP 2390)):
[KCrash Handler]
#6  0x000000e0 in ?? ()
#7  0xb4577ce9 in QMetaObject::cast (this=0xb555e20c <QAction::staticMetaObject>, obj=0x8abde10) at kernel/qmetaobject.cpp:339
#8  0xb631c7c2 in qobject_cast<QAction*> (object=0x8abde10) at /opt/kde5qt5/include/QtCore/qobject.h:522
#9  0xb631f82b in KActionConflictDetector::eventFilter (this=0x848e7e8, watched=0x8abde10, event=0xbf8679a4) at /home/diau/git/kf5/frameworks/kxmlgui/src/kactionconflictdetector.cpp:44
#10 0xb456fb00 in QCoreApplicationPrivate::sendThroughApplicationEventFilters (this=0x844b040, receiver=0x8abde10, event=0xbf8679a4) at kernel/qcoreapplication.cpp:1014
#11 0xb4f49f60 in QApplicationPrivate::notify_helper (this=0x844b040, receiver=0x8abde10, e=0xbf8679a4) at kernel/qapplication.cpp:3462
#12 0xb4f47a09 in QApplication::notify (this=0xbf86852c, receiver=0x8abde10, e=0xbf8679a4) at kernel/qapplication.cpp:2940
#13 0xb456f901 in QCoreApplication::notifyInternal (this=0xbf86852c, receiver=0x8abde10, event=0xbf8679a4) at kernel/qcoreapplication.cpp:937
#14 0xb73fa745 in QCoreApplication::sendEvent (receiver=0x8abde10, event=0xbf8679a4) at /home/diau/git/qt5/qtbase/include/QtCore/../../src/corelib/kernel/qcoreapplication.h:237
#15 0xb73f71d0 in QQuickWindow::sendEvent (this=0x8e80248, item=0x8abde10, e=0xbf8679a4) at items/qquickwindow.cpp:2396
#16 0xb73f1d99 in QQuickWindowPrivate::setFocusInScope (this=0x8e83738, scope=0x0, item=0x8e7fa68, reason=Qt::ActiveWindowFocusReason, options=...) at items/qquickwindow.cpp:788
#17 0xb73df154 in QQuickItem::setFocus (this=0x8e7fa68, focus=true, reason=Qt::ActiveWindowFocusReason) at items/qquickitem.cpp:6313
#18 0xb73ef8a8 in QQuickWindow::focusInEvent (this=0x8e80248, ev=0xbf86816c) at items/qquickwindow.cpp:256
#19 0xb497c4cb in QWindow::event (this=0x8e80248, ev=0xbf86816c) at kernel/qwindow.cpp:1914
#20 0xb73f2e64 in QQuickWindow::event (this=0x8e80248, e=0xbf86816c) at items/qquickwindow.cpp:1338
#21 0x080a11ad in DesktopView::event(QEvent*) ()
#22 0xb4f4a0a4 in QApplicationPrivate::notify_helper (this=0x844b040, receiver=0x8e80248, e=0xbf86816c) at kernel/qapplication.cpp:3487
#23 0xb4f47a09 in QApplication::notify (this=0xbf86852c, receiver=0x8e80248, e=0xbf86816c) at kernel/qapplication.cpp:2940
#24 0xb456f901 in QCoreApplication::notifyInternal (this=0xbf86852c, receiver=0x8e80248, event=0xbf86816c) at kernel/qcoreapplication.cpp:937
#25 0xb4974759 in QCoreApplication::sendSpontaneousEvent (receiver=0x8e80248, event=0xbf86816c) at ../../include/QtCore/../../src/corelib/kernel/qcoreapplication.h:240

(In reply to comment #2)

sorry, comment for wrong bug ;)

apparently happens here on a second system (with everything at the same revision than the other system)

22:37 < notmart> bshah: nope, i noticed later it was an old git revision of plasma-framework
22:37 < notmart> so on the current one doesn't happen anymore for me
22:37 <bshah> also I can not with todays build
22:37 < notmart> so definitely gone away in recent builds