QMainWindow::saveState, restoreState and perspectives

Suggestion: QMainWindow - make it possible to retrieve information about docked windows and toolbars using saveStates QByteArray.

I.e. to get information about toolbars and dockwidgets from QByteArray (names, sizes, visibility) Now one can only get information from QMainWindow ) eg.:

QByteArray activePerspective = mainWindow.saveState();
QByteArray inactivePerspective = perspective2;

QPixmap pixmap = createThumbnailViewFromPerspective( activePerspective);
printListOfVisibleDockWidgets( inactivePerspective );