Effective clipping region

Hi,

For windowed mode, in both FF3.6 and FF4.0 for windows, it's easy to 
determine the actual clipping region (relative to the browser window, 
i.e. browser drawn scrollbars, etc. overlapping plugin) with standard 
windows clipping functions. However this is not specified by NPAPI - but 
something OS-typical.

For FF3.6/windowless mode, it is also possible to get the actual 
clipping region by e.g. using GetClipBox(), however I found it to be 
only valid whenever the browser calls NPP_SetWindow().

With FF4.0/windowless mode and the new async rendering model however, I 
did not find a means so far to query the actual clipping region. Is this 
possible at all anymore? And if not, shouldn't it be (and also being 
part of the NPAPI specification?)?
Maybe I'm missing something, but NPP_SetWindow.NPWindow's clip rect does 
not seem to carry the desired information, as well as 
NPP_HandleEvent.NPEvent.WM_PAINT.lParam (which also contains a pointer 
to a rect - iirr rather the same as clip rect).

Thanks,
Rodion