When composing HTML-Messages Thunderbird creates a huge mess, especially when I use a different font such as Courier New. Instead of inserting <font face="Courier New, Courier, monospace"> at the beginning of the email and </font> at the end TB inserts hundrets of such tags <font face="Courier New, Courier, monospace"> all over the email. Each paragraph, each list item each table object gets enclosed with the font tag. Every time some text is copied or moved within an email more of these font tags are inserted. When adding a list bullet those font tags are added. When the list bullet is removed the font tags stay in the email. After editing an email for a while the email is full of useless repeated "empty" font tags such as <font face="Courier New, Courier, monospace"></font>. Often the tags are not just "empty" <font face="Courier New, Courier, monospace"> <p> <br></font>. Very often those empty font tags are heavily nested such as: <font face="Courier New, Courier, monospace"> <p> <br> <font face="Courier New, Courier, monospace"> <font face="Courier New, Courier, monospace"> <p> <p></font> </font></font>. When inserting text in such an email it frequently happens that the cursor is trapped in a "unbalanced" tag position causing the font to change randomly. Deleting text with the delete key also breaks the "balance" (begin and closing tags) of the font tags causing to change the font in larger text areas. When moving the cursor within an email with broken tag balances causes the cursor to jump to random positions. This makes HTML-Editing a nightmare. Also creating tables, appending rows or columns are horrible functions and do not work. One can only delete the table and creat a new one. Setting column with is impossible. After TB cannot generate working and clean HTML-structures since ever it should provide an HTML-edit mode where we can insert and remove html-tags as needed. Please improve this desaster. Thank you, Uri