User Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:79.0) Gecko/20100101 Firefox/79.0

Steps to reproduce:

1. I create a new list in a clean empty email.
2. I click the numbered list button, then type "typed outer 1"
3. I type enter, then tab (to indent to next indent level) then click the bullet list button and type "bullet inner 1" and enter
4. type "bullet inner 2" and enter
5. type shift-tab to unindent, then type "typed outer 2"
6. enter twice to complete the list.

Note note related bug 1574398 which is marked as resolved, which seems to suggest that the correct behaviour occurs in Firefox. It however does not occur in Thunderbird.

I note that I can also produce wrong behaviour by inserting HTML:

<ol>
<li>outer 1</li>
<ul>
<li>inner 1</li>
<li>inner 2</li>
</ul>
<li>outer 2</li>
</ol>

This also gives the wrong behaviour as below.

I note there is some discussion suggesting that an <ul> should not be placed within an <ol> (https://bugzilla.mozilla.org/show_bug.cgi?id=1574398#c3) however as noted there, this code has been generated by the GUI and is therefore not an input error.

Note that this bug is for Thunderbird 68 (Ubuntu 18.04). I will attempt testing with a newer version and updated accordingly.

Actual results:

1. typed outer 1
   • bullet inner 1
   • bullet inner 2
2. typed outer 2 <---- NOTICE '3' at the start!!

Expected results:

1. typed outer 1
   • bullet inner 1
   • bullet inner 2
2. typed outer 2

** Bugzilla seems to have done something to my 'actual results' and has messed up the input text with Markdown or somesuch. The final line has a '3.' at the start in Thunderbird 68.