Thank you for this plugin! I plan to use it more, in the future, to compare Orwell's 1984 translations, but I just gave it a try for testing purposes and noticed the HTML output to file will be great for this use case, as it displays the text differences side-by-side in a very synchronized fashion.
some quick notes:
- The toolbar button click could default directly to the "Compare" action, instead of triggering the menu opening, IMO...
- Calibre UI will hang for a while during TextDiff, so at first I wasn't sure that this was just a temporary halt.
- The "Save output as ebook" action sometimes returns an error, I forgot to take note of what it was about
- Under Dark theme, it's best to use the "Save output to file", as the on-screen output isn't tuned to that color palette