There are currently issues with java in Firefox3 that prevent the openinfocard id selector to function reliably. For the time beeing: If you want to use/try the openinfocard id selector then please use Firefox 18.104.22.168.
Mozilla and Sun are changing the way java works in Firefox and this seems to be problematic. While I could work around some issues, there is no workaround for others. Using 6u10 makes things worse.
The current problems break all java extensions in Firefox3 that use the jar file loading technique recommended by the Mozilla Developer Center.
IdentityServer & Heidelberg on Channel9
2 days ago