In Thunderbird from v102 (I think) onwards, a new message is indicated by a yellow/orange diamond indicator to the left of the subject heading. Unlike other "status flag" elements in the message list ("Read status", "Starred", "Priority" and so on) – which are columns that can be repositioned or removed like any other column – this indicator seems to be implemented as an integral part of the "Subject" column, and the user can't do anything in the UI to remove it. (You can see from the HTML in the screenshot that it uses a placeholder img element inside the table cell that contains the subject line: the default CSS renders this img with the yellow/orange graphic.) I could get rid of this indicator easily enough with some code in userChrome.css. However, that's not consistent with "Read status", "Starred", "Priority" etc, which a user can simply remove with the column chooser in the UI. Am I missing something: is there a way of removing this "new message" indicator without custom CSS?