I think I have discovered why I am having so much trouble with Icecat on
Fedora. I had installed Icecat from the website and NOT from the Fedora
repositories. If I do this then the browser does not work correctly.
However if on Fedora 21 I use the available package then it works OK and
I am able to copy my FF profile across including passwords etc and all
is fine. The same applies to Fedora 23, the official repositories
versions of Icecat work but the downloadable ones do not.
I guess this means for Fedora at least Icecat must be compiled from
source specifically for Fedora. It also means that I am unable to run
the latest version until such time as the repositories are updated
(which for Fedora 21 will not now happen).
It is a shame that the downloadable versions of Icecat are not fully
stand-alone and that there does not seem to be a portable version which
can be run from a usb stick (at least not one I have found).
So for now I have v38.3 on Fedora 21 and 38.5.0 on Fedora 23.
If anyone can point me to the correct instructions for compiling from
source I would very much appreciate it.
Stuart