How to close/destroy IWebBrowser cleanly ?

When the WebBrowser2 component close, some threads continue to work :
- sound continue to play even after ExitInstance (resulting in
unstoppable sound playing without any window )
- requests continue to be processed (resulting in opening many IE
instance in one case on a page refreshed automatically )
Forcing a navigation, like navigate("about:blank"), close the threads
but I'm worried, it could do something worse unexpectly.
The issue seem related to WM_PARENTNOTIFY not beeing sent to "Internet
Explorer_Hidden".
The issue affect all the little browser applications I tried. It's easy
to reproduce : Generate a template MDI project with an htmlview and
point the view to http://www.flashsound.com then close the childview.
This is an exemple : most page with flash have the same issue. I may
miss something since IE and Maxthon are working ok. Any ideas ?

Manu

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