Steps to reproduce: In a contenteditable div, 1. Input any character to the message body, then enable 2-Set Hangul input method. 2. In Mail, go to menu Format > Style > Bold / Italic / Underline (also you can press 'Command + B', 'Command + I' or 'Command + U'). 3. Type any Korean characters (e.g. "한글(gksrmf)" ) after the characters (typed in Step 1), check the results. <rdar://problem/6988023>
Created attachment 64036 [details] proposed fix
Committed <http://trac.webkit.org/changeset/65127>.