Hi Jelby,
The aberration is another instance of the calibre process - sort of
I get exactly the same with my mail client. when I hit the reply button it opens a Reply window that shows as another item in the taskbar, which gets grouped (that's a Windows setting not a 3rd party tweak) with the main icon. And the Reply window shows as a separate Application, but not as a separate Process.
So I'm assuming the 'aberrant' taskbar icon represents the prince.exe program
I'm OK with it now, but it may 'disturb' other Windows users - on the other hand they may not even notice it
So... bottom line is that it's ready to go in Windows (icons aside). I wont be doing any quality checking of the output PDF - just thought I'd help by doing some basic 'does it work' tests.
Cheers BR