Hi Doitsu,
Thank you for your work
Some feedback. I didn't have any problem installing it but when I run it in the Editor it always removes my docked panel (bottom left on my setup) for the standard calibre Check Book. It's easy enough to go back into View to recheck 'Check Book' but I'd rather not have to do that if possible. Running Check Book also puts it back in place.
Also EpubCheck automatically docks itself along the whole of the top of the Editor window. It allows itself to be docked elsewhere (I put it alongside 'Check Book') but when it's run it always moves itself back along the top. Is this deliberate?