Hello,
please go to
http://www.dokuwiki.org/playground:sandbox
and clear the whole text (Ctrl+A DELETE).
Now type in "aaaa" and hit the HOME key to get to the first row. Now type in "bbbb" - the text is now getting visually overwrited. It does not behave correctly. Now hit enter - the text is rendered ok after the enter key.
I am also submitting Google Chrome bug report. Its not sure where the bug is yet.