The new TextField in WebKit allows the user to change the style of the text. For example, you can highlight a portion of a TextField's text, and press Cmd-B to make it bold. The style will be kept until the TextField loses focus. At that point the style is removed, but the characters are still laid out as if the style was applied. Styles are also not (immediately) removed when rich text is pasted into the text field.
Created attachment 7390 [details]
*** This bug has been marked as a duplicate of 6989 ***