Comment 13 for bug 234188

It seems that swfdec does not yet have fullscreen support--see http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=476867

I cannot find anything about fullscreen support in libflash. But looking at the source package (https://launchpad.net/ubuntu/+source/libflash/), it has not changed since at least feisty, and has only been incremented by very small numbers (0.4.10 to 0.4.13) before that. So I suspect it's horribly out of date.