here a short screen video, its better than every explanation.
look at the tab changes.
for the gaming pieces i used sync object.http://youtu.be/vZKs1CUH1zk
for other reader,
r197 was fine, i tested always within tabs.
pause on unfocus = no (problem happens also in open tab)
i think i used at all multipleayer event a log entry.
i did NOT hide or show this gaming pieces in any way.
some new info: if the game runs in seperate browser window everything is ok...
(did not mean it is solved)
same issue in firefox and chrome browser ...
the gaming pieces also get invisible at client if the host window go minimized
and reappear at client if host window goto normal state.
that is not wrote in manual. also not expected. (not saw a event Multiplayer.Inactive/Activate)
if opponent minimized his window or change tab all sprites disappear unwanted at client side.