Bug 186360

Version:            (using KDE 4.2.1)
OS:                Linux
Installed from:    SuSE RPMs

Kwin is crashing when using present windows effect under right circumstances

Prerequisites: 
- enabled desktop effects
- enabled "present windows" effects (I've set mine to Regular grid and it triggers when moving mouse to top-left corner - all desktops)
- multiple virtual desktops (minumum 2)

Steps to reproduce:

- open e.g. dolphin on first desktop
- go to second desktop and open another dolphin window
- trigger "present all windows" (ctrl + f10 or mouse configured corner)
- switch a few times between two different windows of dolphin
- stop switching, choose one window
- close dolphin window on active virtual desktop
- trigger present windows
- crash

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Application: KWin (kwin), signal SIGSEGV
[?1034h[Thread debugging using libthread_db enabled]
[Current thread is 1 (Thread 0xb555e730 (LWP 30410))]

Thread 1 (Thread 0xb555e730 (LWP 30410)):
[KCrash Handler]
#6  0xb32196f0 in KWin::PresentWindowsEffect::setHighlightedWindow (this=0x82410b8, w=0x80f8c40) at /usr/src/debug/kdebase-workspace-4.2.1/kwin/effects/presentwindows.cpp:1270
#7  0xb3224b45 in KWin::PresentWindowsEffect::rearrangeWindows (this=0x82410b8) at /usr/src/debug/kdebase-workspace-4.2.1/kwin/effects/presentwindows.cpp:484
#8  0xb322522b in KWin::PresentWindowsEffect::setActive (this=0x82410b8, active=true, closingTab=false) at /usr/src/debug/kdebase-workspace-4.2.1/kwin/effects/presentwindows.cpp:1153
#9  0xb3225b9a in KWin::PresentWindowsEffect::borderActivated (this=0x82410b8, border=KWin::ElectricTopLeft) at /usr/src/debug/kdebase-workspace-4.2.1/kwin/effects/presentwindows.h:99
#10 0xb806b0e7 in KWin::EffectsHandlerImpl::borderActivated (this=0x8165648, border=KWin::ElectricTopLeft) at /usr/src/debug/kdebase-workspace-4.2.1/kwin/effects.cpp:321
#11 0xb7ff5c25 in KWin::Workspace::checkElectricBorder (this=0x8104868, pos=@0xbfdd1c94, now=36446057) at /usr/src/debug/kdebase-workspace-4.2.1/kwin/workspace.cpp:2260
#12 0xb7ff5d32 in KWin::Workspace::electricBorderEvent (this=0x8104868, e=0xbfdd222c) at /usr/src/debug/kdebase-workspace-4.2.1/kwin/workspace.cpp:2324
#13 0xb801a445 in KWin::Workspace::workspaceEvent (this=0x8104868, e=0xbfdd222c) at /usr/src/debug/kdebase-workspace-4.2.1/kwin/events.cpp:410
#14 0xb8008032 in KWin::Application::x11EventFilter (this=0xbfdd2544, e=0xbfdd222c) at /usr/src/debug/kdebase-workspace-4.2.1/kwin/main.cpp:359
#15 0xb71bfb9e in ?? () from /usr/lib/libQtGui.so.4
#16 0xb71d05f5 in QApplication::x11ProcessEvent(_XEvent*) () from /usr/lib/libQtGui.so.4
#17 0xb71fa0ca in ?? () from /usr/lib/libQtGui.so.4
#18 0xb65789a8 in g_main_context_dispatch () from /usr/lib/libglib-2.0.so.0
#19 0xb657c063 in ?? () from /usr/lib/libglib-2.0.so.0
#20 0xb657c221 in g_main_context_iteration () from /usr/lib/libglib-2.0.so.0
#21 0xb6f1bfb8 in QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#22 0xb71f97c5 in ?? () from /usr/lib/libQtGui.so.4
#23 0xb6ef001a in QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#24 0xb6ef01da in QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) () from /usr/lib/libQtCore.so.4
#25 0xb6ef2895 in QCoreApplication::exec() () from /usr/lib/libQtCore.so.4
#26 0xb7160777 in QApplication::exec() () from /usr/lib/libQtGui.so.4
#27 0xb800aeba in kdemain (argc=2, argv=0xbfdd2714) at /usr/src/debug/kdebase-workspace-4.2.1/kwin/main.cpp:519
#28 0x080487b2 in main (argc=0, argv=0x82b9330) at /usr/src/debug/kdebase-workspace-4.2.1/build/kwin/kwin_dummy.cpp:3
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