REGRESSION: ReactOS doesn't shutdown via Shell Explorer

ReactOS doesn't shut-down when you click on "Start menu -> Turn off -> 'Do you want to shutdown?' -> 'Yes'" : it stops at "saving your settings" message, but you can still move the mouse and click elsewhere and move the window. If then you try to shutdown ReactOS via command-line : "shutdown -s", it returns an error code (see attached picture and debug-log-1.log where you can see at the end my different attempts to shut it down).
This bug seems to exist since revision 52446 (I tested rev.52445, rev.52444 and rev.52443 without any problem).

On the opposite, when you DIRECTLY shuts down via "shutdown -s" (i.e. without trying to shut-down via "Start menu -> ..."), ReactOS shuts down very well... (see debug-log-2.log).

(tested on VirtualBox 4.0.8 r71778. Host machine: Windows 7 Pro, Intel Core i7).