If UTF-8 display and multibyte display are both enabled, when typing multibyte character(e.g.: Chinese) with Ctrl+B, +U or +K(i.e. bold, underline and colors), the nick(<nick> text) will be disappeared.
Try: (the following text is in Big-5 coding)
¤µ¤é¬O¤G¹s¹s¤»¦~¤G¤ë¤Q¤K¤é
12¤µ¤é¬O¤G¹s¹s¤»¦~¤G¤ë¤Q¤K¤é
Either UTF-8 display or multibyte display is enabled, this problem is not happened.