OS X Bug where keypresses are wrongly routed in a QStackedWidget with NativeWindow widget and QTextEdit

I've got a QStackedWidget with two child widgets. One is a QGLWidget, the other a QTextEdit.

I can click the QTextEdit and type normally, then I switch to the other widget and back and text input has broken.

Some characters work, eg 'q' but others eg 'w' do not. What's more I can see the menu bar flashing when I press q. Q has a menu action!

I'm debugging Qt source and sure enough in the working state, my QTextEdit gets keyPressEvents as expected. NSWindow sendEvent -> QCocoaView keyDown:

0 MyInputWidget::keyPressEvent MyInputWidget.cpp 115 0x101715e37
1 QWidget::event qwidget.cpp 8422 0x1076927ef
2 QFrame::event qframe.cpp 557 0x107b02f55
3 QAbstractScrollArea::event qabstractscrollarea.cpp 996 0x107bb5177
4 QTextEdit::event qtextedit.cpp 1070 0x107b97efd
5 QApplicationPrivate::notify_helper qapplication.cpp 4562 0x10761f665
6 QApplication::notify qapplication.cpp 4003 0x107627b15
7 MyQApplication::notify MyQApplication.cpp 278 0x1010c9f64
8 QCoreApplication::notifyInternal qcoreapplication.cpp 949 0x108c56310
9 QCoreApplication::sendSpontaneousEvent qcoreapplication.h 234 0x107584ed7
10 qt_sendSpontaneousEvent qapplication.cpp 5560 0x10761c72b
11 QKeyMapper::sendKeyEvent qkeymapper_mac.cpp 1014 0x1076c60c0
12 QKeyMapperPrivate::translateKeyEvent qkeymapper_mac.cpp 886 0x1076c760d
13 qt_dispatchKeyEvent qt_cocoa_helpers_mac.mm 839 0x1075ae40b
14 -[QCocoaView keyDown:] qcocoaview_mac.mm 935 0x10759ca49
15 -[NSWindow sendEvent:] 0x7fff8c5647ac
16 -[QCocoaWindow sendEvent:] qcocoasharedwindowmethods_mac_p.h 183 0x1075a2338
17 -[NSApplication sendEvent:] 0x7fff8c4fda55
18 -[QNSApplication sendEvent:] qcocoaapplication_mac.mm 186 0x1075a945a
19 -[NSApplication run] 0x7fff8c4940c6
20 QEventDispatcherMac::processEvents qeventdispatcher_mac.mm 615 0x1075b737e
21 QEventLoop::processEvents qeventloop.cpp 149 0x108c543d4
22 QEventLoop::exec qeventloop.cpp 204 0x108c54814
23 QCoreApplication::exec qcoreapplication.cpp 1221 0x108c59d82

In the broken state, the keys which do make it to the QTextEdit::keyPressEvent have a different stack, and the events are now routed via NSWindow keyDown -> NSWindow keyDown -> NSMenu performKeyEquivalent:

0 MyInputWidget::keyPressEvent MyInputWidget.cpp 115 0x101715e37
1 QWidget::event qwidget.cpp 8422 0x1076927ef
2 QFrame::event qframe.cpp 557 0x107b02f55
3 QAbstractScrollArea::event qabstractscrollarea.cpp 996 0x107bb5177
4 QTextEdit::event qtextedit.cpp 1070 0x107b97efd
5 QApplicationPrivate::notify_helper qapplication.cpp 4562 0x10761f665
6 QApplication::notify qapplication.cpp 4003 0x107627b15
7 MyQApplication::notify MyQApplication.cpp 278 0x1010c9f64
8 QCoreApplication::notifyInternal qcoreapplication.cpp 949 0x108c56310
9 QCoreApplication::sendSpontaneousEvent qcoreapplication.h 234 0x107584ed7
10 qt_sendSpontaneousEvent qapplication.cpp 5560 0x10761c72b
11 QKeyMapper::sendKeyEvent qkeymapper_mac.cpp 1014 0x1076c60c0
12 QKeyMapperPrivate::translateKeyEvent qkeymapper_mac.cpp 886 0x1076c760d
13 qt_dispatchKeyEvent qt_cocoa_helpers_mac.mm 839 0x1075ae40b
14 -[QCocoaMenu menuHasKeyEquivalent:forEvent:target:action:] qcocoamenu_mac.mm 189 0x1075ff873
15 -[NSMenu _performKeyEquivalentWithDelegate:] 0x7fff8c60575b
16 -[NSMenu _performKeyEquivalentWithDelegate:] 0x7fff8c6059b6
17 -[NSMenu performKeyEquivalent:] 0x7fff8c605452
18 -[NSApplication _handleKeyEquivalent:] 0x7fff8c604175
19 -[NSWindow keyDown:] 0x7fff8cb2fb82
20 -[NSWindow sendEvent:] 0x7fff8c5647ac
21 -[QCocoaWindow sendEvent:] qcocoasharedwindowmethods_mac_p.h 183 0x1075a2338
22 -[NSApplication sendEvent:] 0x7fff8c4fda55
23 -[QNSApplication sendEvent:] qcocoaapplication_mac.mm 186 0x1075a945a
24 -[NSApplication run] 0x7fff8c4940c6
25 QEventDispatcherMac::processEvents qeventdispatcher_mac.mm 615 0x1075b737e
26 QEventLoop::processEvents qeventloop.cpp 149 0x108c543d4
27 QEventLoop::exec qeventloop.cpp 204 0x108c54814
28 QCoreApplication::exec qcoreapplication.cpp 1221 0x108c59d82

I've checked during MyInputWidget::keyPressEvent and MyInputWidget is indeed QApplication::focusWidget() in both cases.

If I add an event filter, I can see that the KeyPresses are being routed correctly when I switch to the QGLWidget page, but not when I switch to the QTextEdit page (they are sent to the NSMenu