Hi,
This issue occurs in IE (I tested with 8), and not Firefox, at least:
1) Type something in an empty editor.
2) Press Ctrl+A to select the text just typed.
3) Press the Insert Hyperlink button, and insert a hyperlink.
4) Place the cursor at the end of the hyperlink, and type something.
5) Note that the hyperlink 'extends' to what has been just typed in (4). Press Enter a few times, and enter some text. The hyperlink also applies to what has been just typed.
6) Change the editor to Code view. Could this issue be happening because everything is wrapped in a <div> in IE?
Thanks!