I found a post here: https://bugs.launchpad.net/ubuntu/+source/nspluginwrapper/+bug/177856 that seems to have cured the problem for me.
It involves installing this version of the nsplugin wrapper file:
I found a post here: https:/ /bugs.launchpad .net/ubuntu/ +source/ nspluginwrapper /+bug/177856
that seems to have cured the problem for me.
It involves installing this version of the nsplugin wrapper file: