When creating tiled subwindows using tileSubWindows on a QMdiArea, setting the order to be QMdiArea::CreationOrder has no effect. The bug can be reproduced by opening the mdi example in the mainwindows examples and opening two documents. Click the "Tile" item on the Window menu and the windows are tiled out of order.

The rearranger in qmdiarea.cpp and the call to const QList<QMdiSubWindow *> subWindows = subWindowList(activationOrder, reverseList); has the activation order and a bool flag passed to it. The flag determines if the widgets are appended or prepended to a QList of widgets which is then returned. The items appear to be sorted by the list independent of whether the creation order flag is set in Qt.