Wrong behavior about compiz?

[Rockmen Jack]

Hi,all
   Compiz behaves differently from metacity when "Show Desktop Button"
was ready clicked:
   When I click the "Show Desktop Button", all shown windows will be
minimized, but then if I open a new window,compiz will show all the
minimized windows plus the new one, but for metacity, only the new one
is showed.
  I guest that when that new window is showed, the "Show Desktop Button"
will be released(as seen from the appearance of the button), and compiz
mistakes this as a show-all-window message.

Thanks all.