when a QML scene is embedded in a QQuickWidget and the Shortcut {} element is used, the shortcut won't actually work, because in qquickshortcut.cpp, the matcher does:

static bool qQuickShortcutContextMatcher(QObject *obj, Qt::ShortcutContext context)
{
switch (context) {
case Qt::ApplicationShortcut:
return true;
case Qt::WindowShortcut:
while (obj && !obj->isWindowType()) {
obj = obj->parent();
if (QQuickItem *item = qobject_cast<QQuickItem *>(obj))
obj = item->window();
}
return obj && obj == QGuiApplication::focusWindow();
default:
return false;
}
}

so it will never match as the internal QWindow of a QQuickWidget will never be the qguiapplication's focusWindow