While trying to update this answer to the question What part of tag score do I not understand yet?, I came across the undefined text in the Answer text box.

I clicked on the edit link to modify the answer. I clicked in the Answer text box and when I press Strong, Emphasis, Hyperlink or Image icons in the toolbar, I see undefined text surrounding the tags. All the other icons work fine.


So, I tried to edit a different answer to question Bug in parsing python multiline strings. I don't find any error in this one.

No error

I don't know if it is the screenshot that is causing this problem in the first answer but not in the second answer. I get the same undefined text even when I press Ctrl + B or Ctrl + I.

I am using Google Chrome browser 13.0.782.107 on Windows 7 machine.

  • Using the edit link on the same answer does not replicate the problem for me, nor on my own answers in FireFox 5. Commented Aug 5, 2011 at 11:52
  • 1
    @staticbeast: I just tried to edit the same answer (the first one) in IE 9.0 and it seems to work fine. Looks like this happens only in Google Chrome browser.
    – user162697
    Commented Aug 5, 2011 at 11:55
  • @Siva - not sure about that now; we have a repro, at least Commented Aug 5, 2011 at 12:12

2 Answers 2


It appears this is another incarnation of this infamous heisenbug. I couldn't reproduce everything you mentioned, but some of it; and after removing a few RegExp.$1 usages around the italic/bold processing, the issue was indeed gone. Hence this shouldn't happen anymore after the next build.

I'm going to kill all uses of this feature sooner rather than later; it's deprecated anyway, and it's a terrible JavaScript feature to begin with.


Reproduced in chrome in the same version as an anonymous user.

The error occurs not when bold is used, but when it is used and then you try to remove it:

  1. Apply bold: **strong text**
  2. Highlight text and click to unbold: **undefined**strong text**undefined**

The same holds for Italics and linking inside a link (although that may just be incidental bad practice).


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