Yes, these are all software configurations that have never existed at the same time. That is why we are pushing hard to upgrade the server to the latest release of Windchill. The current server software is over a year old and has never seen Windows 8 or 8.1 along with IE 10 or 11. Using the config.pro option for mozilla is the only alternative and we've already seen it not work as expected with machines that have already been upgraded to IE 10 or 11.
We truly understand the challenges this creates for everyone and we're doing all we can to correct it. Hopefully we'll have good news after the holidays.
In the mean time, if you have a Win8 or 8.1 machine with IE 10 or 11, you may want to stay away from Windchill while working with Creo unless you can validate your configuration is working properly. Hopefully you still have access to a Win7 machine with IE 9 if you want to keep Creo connected with Windchill.