The :before and :after selectors in bullet lists (for example) are standard, though perhaps a bit controversial. We need them to replace the ugly and outdated standard bullet symbols with normal characters.
In French we use dashes for dialogue (conversation) sequences in novels, and may wish to experiment with different dash lengths for stylistic reasons; they should not go in the html.
The Kobo display engine allows these selectors (to use it in place of ADE you have to rename your file with the kepub.epub suffix). Their use complies perfectly with current standards, and my files pass all the tests recommended by Sigil. Please could someone explain why ADE ignores them?