application crashes if you remove the toolbar from the main window (QMainWindow)

application crashes if you remove the toolbar from the main window (QMainWindow) calling removeToolBar

this->removeToolBar(this->toolBar);

Crash report:

Process: Warehouse [48761]
Path: /Users/***/Documents/workspace/Warehouse/bin/Warehouse.app/Contents/MacOS/Warehouse
Identifier: com.yourcompany.Warehouse
Version: ??? (???)
Code Type: X86-64 (Native)
Parent Process: eclipse [23865]

Date/Time: 2009-11-24 23:43:06.713 +0100
OS Version: Mac OS X 10.6.2 (10C540)
Report Version: 6

Interval Since Last Report: 172361 sec
Crashes Since Last Report: 34
Per-App Interval Since Last Report: 12101 sec
Per-App Crashes Since Last Report: 13
Anonymous UUID: B066DCB6-C9BF-4F81-B28A-3B18F863C2A1

Exception Type: EXC_BAD_ACCESS (SIGSEGV)
Exception Codes: KERN_INVALID_ADDRESS at 0x0000000000000000
Crashed Thread: 0 Dispatch queue: com.apple.main-thread

Thread 0 Crashed: Dispatch queue: com.apple.main-thread
0 QtGui 0x000000010012ada3 QHash<void*, QToolBar*>::erase(QHash<void*, QToolBar*>::iterator) + 99
1 QtGui 0x000000010012a639 QMainWindowLayout::removeFromMacToolbar(QToolBar*) + 441
2 QtGui 0x00000001004dc781 QMainWindow::removeToolBar(QToolBar*) + 33
3 com.yourcompany.Warehouse 0x0000000100003b8c MainWindow::setApplicationToolbar(QList<QAction*>) + 76 (MainWindow.cpp:144)
4 com.yourcompany.Warehouse 0x000000010002b789 ApplicationOrderForm::itemSelected(QString const&, QTreeWidgetItem*) + 189 (ApplicationOrderForm.cpp:131)
5 com.yourcompany.Warehouse 0x00000001000358a7 ApplicationOrderForm::qt_metacall(QMetaObject::Call, int, void**) + 251 (moc_ApplicationOrderForm.cpp:92)
6 QtCore 0x0000000100cd72a4 QMetaObject::activate(QObject*, QMetaObject const*, int, void**) + 644
7 com.yourcompany.Warehouse 0x0000000100034a2d MainWindow::applicationItemSelected(QString const&, QTreeWidgetItem*) + 85 (moc_MainWindow.cpp:100)
8 com.yourcompany.Warehouse 0x00000001000042a6 MainWindow::on_applicationsTW_currentItemChanged(QTreeWidgetItem*, QTreeWidgetItem*) + 1150 (MainWindow.cpp:111)
9 com.yourcompany.Warehouse 0x0000000100034b2a MainWindow::qt_metacall(QMetaObject::Call, int, void**) + 250 (moc_MainWindow.cpp:86)
10 QtCore 0x0000000100cd72a4 QMetaObject::activate(QObject*, QMetaObject const*, int, void**) + 644
11 QtGui 0x0000000100644c5d QTreeWidget::currentItemChanged(QTreeWidgetItem*, QTreeWidgetItem*) + 61
12 QtGui 0x000000010064c61b QTreeWidget::qt_metacall(QMetaObject::Call, int, void**) + 811
13 com.yourcompany.Warehouse 0x000000010003509b FwTreeWidget::qt_metacall(QMetaObject::Call, int, void**) + 41 (moc_FwTreeWidget.cpp:64)
14 QtCore 0x0000000100cd72a4 QMetaObject::activate(QObject*, QMetaObject const*, int, void**) + 644
15 QtGui 0x000000010062260d QItemSelectionModel::currentChanged(QModelIndex const&, QModelIndex const&) + 45
16 QtGui 0x00000001006228fe QItemSelectionModel::setCurrentIndex(QModelIndex const&, QFlags<QItemSelectionModel::SelectionFlag>) + 142
17 QtGui 0x00000001005ceca1 QAbstractItemView::mousePressEvent(QMouseEvent*) + 1057
18 QtGui 0x000000010019aeb1 QWidget::event(QEvent*) + 2849
19 QtGui 0x00000001004c247c QFrame::event(QEvent*) + 44
20 QtGui 0x0000000100548937 QAbstractScrollArea::viewportEvent(QEvent*) + 23
21 QtGui 0x00000001005d4c4b QAbstractItemView::viewportEvent(QEvent*) + 363
22 QtGui 0x00000001006110bd QTreeView::viewportEvent(QEvent*) + 493
23 QtGui 0x000000010054ac90 QAbstractScrollAreaFilter::eventFilter(QObject*, QEvent*) + 48
24 QtCore 0x0000000100da7da7 QCoreApplicationPrivate::sendThroughObjectEventFilters(QObject*, QEvent*) + 151
25 QtGui 0x0000000100142cae QApplicationPrivate::notify_helper(QObject*, QEvent*) + 142
26 QtGui 0x000000010014757c QApplication::notify(QObject*, QEvent*) + 1612
27 QtCore 0x0000000100cd196c QCoreApplication::notifyInternal(QObject*, QEvent*) + 124
28 QtGui 0x0000000100142e5c qt_sendSpontaneousEvent(QObject*, QEvent*) + 44
29 QtGui 0x00000001000fcd56 qt_mac_handleMouseEvent(void*, void*, QEvent::Type, Qt::MouseButton) + 1478
30 com.apple.AppKit 0x00007fff815e668f -[NSWindow sendEvent:] + 5409
31 QtGui 0x00000001000f6927 -[QCocoaWindow sendEvent:] + 215
32 com.apple.AppKit 0x00007fff8151be22 -[NSApplication sendEvent:] + 4719
33 com.apple.AppKit 0x00007fff814b2796 -[NSApplication run] + 474
34 QtGui 0x0000000100101c87 QEventDispatcherMac::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 1447
35 QtCore 0x0000000100da7484 QEventLoop::processEvents(QFlags<QEventLoop::ProcessEventsFlag>) + 68
36 QtCore 0x0000000100da7794 QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) + 180
37 QtCore 0x0000000100da8dac QCoreApplication::exec() + 188
38 com.yourcompany.Warehouse 0x0000000100003966 main + 77 (main.cpp:20)
39 com.yourcompany.Warehouse 0x0000000100002c24 start + 52