When you reply to an html email that has an ordered list in it, and you insert comments into the middle of the quoted list, the second half of that list (which is actually a new list, of course) has it's numbering start at 1 again. It should instead have a start attribute added to it so that the numbering does not appear to change. For example, suppose you recieve an email that has a list in it like this: 1. zed 2. foo 3. bar 4. baz and you reply to it. When you insert some comments you get something like this: > 1. zed > 2. foo yadda yadda yadda > 1. bar > 2. baz As you can see, the numbering of the two lists no longer matches up with the original list. If the second list in the reply had a start attribute with a value of 3, then it would look correct. Presumably this applies to Seamonkey Mail as well, but I haven't tested it. Of course, it may be that this behavior is correct in the context of the original HTML Composer.
I can confirm that this happens, in 3.0a1 and also in 126.96.36.199, both on an Intel Mac.