Qt - Remove shortcut -- Ambiguous shortcut overload

Question

Extraneous Information: I am attempting to build an application using Qt. This application features a QMdiArea and a child-window. My child-window will have a menu which can be integrated into the QMdiArea or segregated and attached to the child itself. Though, this is a bit more detail than needed...

Problem: I would like my child-widget to have a menu with a shortcut, "CTRL+W." But, because I am using a QMdiArea, the shortcut is already used causing:

QAction::eventFilter: Ambiguous shortcut overload: Ctrl+W

How can I get rid of this shortcut and claim it within my child widget instead?

Update: Here is what I've tried with no luck:

class MDI : public QMdiArea
{
    Q_OBJECT
    private:
    bool event(QEvent *tEvent)
    {
        if (tEvent->type() == QEvent::KeyPress)
        {
            QKeyEvent* ke = static_cast<QKeyEvent*>(tEvent);
            if (ke->key()== Qt::Key_W && ke->modifiers() & Qt::ControlModifier)
            emit KeyCW();
            return true;
        }
        return QMdiArea::event(tEvent);
    }
public:
signals:
    void KeyCW();
};

This works if I do something as simple as change Qt::Key_W to Qt::Key_L. The key-combo is received and event is thrown. With W, it just never happens. I've also tried moving event to QMainWindow as well as an eventFilter in the subwindow to QMdiArea. It seems that it is a little overly complicated to do something as simple as remove default key-handlers from within QMdiArea.

Answer 1

You can disable this shortcut like this:

for( QAction *action : subWindow->systemMenu()->actions() ) {
    if( action->shortcut() == QKeySequence( QKeySequence::Close ) ) {
        action->setShortcut( QKeySequence() );
        break;
    }
}

Answer 2

You could get rid of the pre-defined close action of the QMdiSubWindow altogether by using Qt::CustomizeWindowHint as additional flag when adding the subwindow.

QMdiSubWindow *subWindow2 = mdiArea.addSubWindow(internalWidget2, 
                                                 Qt::Widget | Qt::CustomizeWindowHint | 
                                                 Qt::WindowMinMaxButtonsHint);