Version:           1.4 (using KDE 4.2.0)
OS:                Linux
Installed from:    Ubuntu Packages

The bug was found on Kubuntu 8.10, 2.6.27-14-generic
KDE 4.2.0
Kontact 1.4

Steps to reproduce:
1. Start Kontact
2. Choose Feed Reader in main window (a tray icon will appear)
3. Right click on this icon -> Quit
You'll get "a fatal error occured" message:
"Tha application Kontact (kontact) crashed and caused the signal 6 (SIGABRT)"

Backtrace details:
Thread 1 (Thread 0xb4a896c0 (LWP 15074)):
[KCrash Handler]
#6 0xb7f3d430 in __kernel_vsyscall ()
#7 0xb591f8a0 in raise () from /lib/tls/i686/cmov/libc.so.6
#8 0xb5921268 in abort () from /lib/tls/i686/cmov/libc.so.6
#9 0xb591872e in __assert_fail () from /lib/tls/cmov/libc.so.6
#10 0xb147a34c in KMKernel::self () from /usr/lib/libkmailprivate.so.4
#11 0xb155186c in kmcrashHadler () from /usr/lib/libkmailprivate.so.4
#12 0xb6cf863a in KCrash::defaultCrashHadler () from /usr/lib/libkdeui.so.5
#13 <signal hadler called>
#14 0xb7f3d430 in __kernel_vsyscall ()
#15 0xb591f8a0 in raise () from /lib/tls/i686/cmov/libc.so.6
#16 0xb5921268 in abort () from /lib/tls/i686/cmov/libc.so.6
#17 0xb595d16d in ?? from /lib/tls/i686/cmov/libc.so.6
#18 0xb5963454 in ?? from /lib/tls/i686/cmov/libc.so.6
#19 0xb5965267 in ?? from /lib/tls/i686/cmov/libc.so.6
#20 0xb5965544b6 in free () from /lib/tls/i686/cmov/libc.so.6
#21 0xb5b410b1 in operator delete () from /usr/lib/libstdc++.so.6
#22 0xb651ad91 in ?? () from /usr/lib/libQtGui.so.4
#23 0xb5cd3d9e in QObject::~Qobject () from /usr/lib/libQtCore.so.4
#24 0xb61c7b0f in QWidget::~QWidget () from /usr/lib/libQtGui.so.4
#25 0xb6519921 in QMainWindow::~QmainWindow () from /usr/lib/libQtGui.so.4
#26 0xb6d6b849 in KMainWindow::~KMainWindow () from /usr/lib/libKdeui.so.5
#27 0xb6dae3c7 in KXmlGuiWindow::~KXmlGuiWindow () from /usr/lib/libKdeui.so.5
#28 0xb70c5688 in KParts::MainWindow::~MainWindow () from /usr/lib/libKparts.so.4
#29 0xb77d5ef7 in Kontact::Core::~Core () from /usr/lib/libkontactinterfaces.so.4
#30 0xb77f30ec in Kontact::MainWindow::~MainWindow () from /usr/lib/libkontactprivate.so.4
#31 0x0804c0ae in _start ()