Hot on the heels of version 0.8, I’m pleased to say I found a quick fix for the problems causing Firefox to fail to shutdown under certain circumstances and have released version 0.8.1 straight to the main download page so please upgrade to the version now available on http://keefox.org/download
There is a remaining issue related to this same underlying problem but I don’t anticipate it causing anyone a significant problem in practice.
Edit: Just to clarify, this is still Beta software - fixing this one bug, while important, is not enough in my opinion to result in a finished product!