[embryo]

Just to add one feature to your miles-long "To do" list.
Something I use continuously in Sigil.
The "H1 H2 H3 H4 H5 p" buttons.
Just select something and change the heading type with one click.
After that, auto create TOC and auto split the HTML files.
The only thing that keeps me still using Sigil.

Thanks for your work anyway :o)