Application override cursor fails to take effect upon re-entering application window during mouse drag

The application override cursor fails to take effect upon re-entering an application window during a mouse drag that was initiated within that window.

The problem can be reproduced by running the MainWindow Application example (qtbase/examples/widgets/mainwindows/application) on Mac OS X, with a QApplication::setOverrideCursor(Qt::OpenHandCursor) call added to the MainWindow constructor.

The open hand cursor is correctly displayed while the cursor moves within the boundaries of the main window.

However:

Initiate a mouse drag within the window and leave the window during the drag; the cursor changes to an arrow as it exits. Continue the drag, moving the cursor back within the window. The arrow cursor continues to be displayed until the conclusion of the mouse drag rather than being replaced with the open hand cursor as it re-enters the window.