This bug has been entered into the Mozilla bug system as Bug 445599 - Firefox 3 seems to "double initialize" Flash.
import flash.external.ExternalInterface;
ExternalInterface.call( "asCallback", (new Date()).getMilliseconds() );
stop();
REM see firefox_3.0.1\mozilla\modules\plugin\base\public\nsPluginLogging.h
set NSPR_LOG_FILE=C:\firefox.log
SET NSPR_LOG_MODULES=Plugin:9, PluginNPP:9, PluginNPN:9
"C:\Program Files\Mozilla Firefox3\firefox.exe" "http://jcmsdev7.turner.com:82/rburke/Firefox3Bug/test_with_embed_tag.html"
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0[332140]]: nsPluginHostImpl::InstantiateEmbeddedPlugin Begin mime=application/x-shockwave-flash, owner=1b5ac80, url=http://jcmsdev7.turner.com:82/rburke/Firefox3Bug/Firefox3Bug.swf
0[332140]]: nsPluginHostImpl::TrySetupPluginInstance Begin mime=application/x-shockwave-flash, owner=1b5ac80, url=http://jcmsdev7.turner.com:82/rburke/Firefox3Bug/Firefox3Bug.swf
0[332140]: nsPluginHostImpl::GetPluginFactory Begin mime=application/x-shockwave-flash, plugin=C:\WINDOWS\system32\Macromed\Flash\NPSWF32.dll
0[332140]: nsPluginHostImpl::UserAgent return=Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.1) Gecko/2008070208 Firefox/3.0.1
0[332140]: nsPluginHostImpl::TrySetupPluginInstance Finished mime=application/x-shockwave-flash, rv=0, owner=1b5ac80, url=http://jcmsdev7.turner.com:82/rburke/Firefox3Bug/Firefox3Bug.swf
0[332140]: nsPluginStreamListenerPeer::InitializeEmbedded url=http://jcmsdev7.turner.com:82/rburke/Firefox3Bug/Firefox3Bug.swf
0[332140]: nsPluginHostImpl::InstantiateEmbeddedPlugin Finished mime=application/x-shockwave-flash, rv=0, owner=1b5ac80, url=http://jcmsdev7.turner.com:82/rburke/Firefox3Bug/Firefox3Bug.swf
0[332140]: nsPluginStreamListenerPeer::OnStartRequest this=1fbee60 request=1cd572c mime=application/x-shockwave-flash, url=http://jcmsdev7.turner.com:82/rburke/Firefox3Bug/Firefox3Bug.swf
0[332140]: nsPluginStreamListenerPeer::OnDataAvailable this=1fbee60 request=1cd572c, offset=0, length=146, url=http://jcmsdev7.turner.com:82/rburke/Firefox3Bug/Firefox3Bug.swf
0[332140]: nsPluginStreamListenerPeer::OnStopRequest this=1fbee60 aStatus=0 request=1cd572c
0[332140]: nsPluginHostImpl::UserAgent return=Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.1) Gecko/2008070208 Firefox/3.0.1
0[332140]: nsPluginStreamListenerPeer::dtor this=1fbee60, url=http://jcmsdev7.turner.com:82/rburke/Firefox3Bug/Firefox3Bug.swf
0[332140]: nsPluginHostImpl::StopPluginInstance called instance=1fa5ac0
0[332140]: nsPluginHostImpl::InstantiateEmbeddedPlugin Begin mime=application/x-shockwave-flash, owner=1b5ac80, url=http://jcmsdev7.turner.com:82/rburke/Firefox3Bug/Firefox3Bug.swf
0[332140]: nsPluginHostImpl::TrySetupPluginInstance Begin mime=application/x-shockwave-flash, owner=1b5ac80, url=http://jcmsdev7.turner.com:82/rburke/Firefox3Bug/Firefox3Bug.swf
0[332140]: nsPluginHostImpl::GetPluginFactory Begin mime=application/x-shockwave-flash, plugin=C:\WINDOWS\system32\Macromed\Flash\NPSWF32.dll
0[332140]: nsPluginHostImpl::UserAgent return=Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.1) Gecko/2008070208 Firefox/3.0.1
0[332140]: nsPluginHostImpl::TrySetupPluginInstance Finished mime=application/x-shockwave-flash, rv=0, owner=1b5ac80, url=http://jcmsdev7.turner.com:82/rburke/Firefox3Bug/Firefox3Bug.swf
0[332140]: nsPluginStreamListenerPeer::InitializeEmbedded url=http://jcmsdev7.turner.com:82/rburke/Firefox3Bug/Firefox3Bug.swf
0[332140]: nsPluginHostImpl::InstantiateEmbeddedPlugin Finished mime=application/x-shockwave-flash, rv=0, owner=1b5ac80, url=http://jcmsdev7.turner.com:82/rburke/Firefox3Bug/Firefox3Bug.swf
0[332140]: nsPluginStreamListenerPeer::OnStartRequest this=25ba740 request=256d3fc mime=application/x-shockwave-flash, url=http://jcmsdev7.turner.com:82/rburke/Firefox3Bug/Firefox3Bug.swf
0[332140]: nsPluginStreamListenerPeer::OnDataAvailable this=25ba740 request=256d3fc, offset=0, length=146, url=http://jcmsdev7.turner.com:82/rburke/Firefox3Bug/Firefox3Bug.swf
0[332140]: nsPluginStreamListenerPeer::OnStopRequest this=25ba740 aStatus=0 request=256d3fc
0[332140]: nsPluginHostImpl::UserAgent return=Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.0.1) Gecko/2008070208 Firefox/3.0.1
0[332140]: nsPluginStreamListenerPeer::dtor this=25ba740, url=http://jcmsdev7.turner.com:82/rburke/Firefox3Bug/Firefox3Bug.swf
0[332140]: nsPluginHostImpl::StopPluginInstance called instance=1be1100
0[332140]: nsPluginHostImpl::Destroy Called
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