Sigil registers itself to Windows as a candidate for opening files it can't open from the shell
Not just MP3 also FLV, AVI , MPG, PDF etc, etc. I appreciate they can be embedded within ePUB3.0, but surely I'm never going to do that by opening them in the Windows shell, would have thought I'd do that from within Sigil after opening the relevant EPUB container.
Could there be an an option in the Windows install to NOT create these 'candidate associations' and remove them if they're already there. Sigil (and plenty of others - browsers etc) 'get in the way' of programs that can do something useful with these files. Firefox puts itself forward as a candidate to handle CBZ's - when I dropped 'file:///users/BetterRed/Downloads/picturebook.cbz' into it -- if offered to download it - into my Downloads folder
With Windows 10 (maybe 8/8.1 too), MS made some radical changes with the way Open With works - Kovid calls in an 'unholy mess' I call it 'Calamities on Toast'. Sadly Nir Sofer is yet to produce an OpenWithView that works with Win10 so there is no simple way of removing these candidate applications, you have to wrangle the registry by hand.
Yes, I do use Open With a lot, as I've always done. Beats me why MS would make something that most of its user base don't use, even harder to use for those of us who do use it. At a guess I'd say 80% of Windows users never right click in the shell, much less use Open With. They click on desktop program icons, and use File Open.
BR