Comment 12 for bug 234188

For no apparent reason, full screen of youtube flash player stopped working again. I removed all other flush player plugins (libflash0c1 and libflash_mozplugin) as recommended in the (german) thread:
http://www.ubuntu-forum.de/artikel/30388/gel%C3%B6st-flash-player-in-firefox-geht-nicht.html
but this didn't change anything.

But about:plugins showed me two Shockwave Flash plugins:
1) File name: libflashplayer.so Shockwave Flash 9.0 r31 and
2) File name: libflashplayer.so Shockwave Flash 9.0 r124

After I completely removed flashplugin-nonfree 9.0.124.0ubuntu1~gutsy1 with synaptic, about:plugins still showed me:
File name: libflashplayer.so Shockwave Flash 9.0 r31

A 'locate libflashplayer' showed me:
~/.mozilla/plugins/libflashplayer.so
~/.mozilla/plugin/libflashplayer.so
which I removed manually and installed flashplugin-nonfree 9.0.124.0ubuntu1~gutsy1 via synaptic again. Now about:plugins correctly just shows:
File name: libflashplayer.so Shockwave Flash 9.0 r124
and full screen flash player works again. I'm not sure whether this was the problem, but I'm guessing that the 'old' flash plugin version wasn't correctly removed by an earlier update and maybe the two plugins had an initialize order problem?