to reproduce: type some text in your html message compose window click on the the "italics" button continue to type, nothing shows up. you have to click back in the message, before your typing will show up. I also found a possibly related problem which is if I select a region of text and then click the "italicize" button, it won't become italized. the selected region just seems to lose focus (going from blue to grey) cntl-i seems to work.
thanks laurel. it is a dup. *** This bug has been marked as a duplicate of 53730 ***
Marking verified as a duplicate.