Double postprocessing when using image dialog hook

[GoogleCodeExporter]

I get:

![![enter image description here][5]][5]

What steps will reproduce the problem?

1. made a page much like the demopage
2. initialized it like the following

<script type="text/javascript">
    function my_dialog(callback){
        alert ("hello");
        var retval = callback("http://xyz.png/x.png");
        return true
    }
    var converter1 = Markdown.getSanitizingConverter();
    var editor1 = new Markdown.Editor(converter1);
    editor1.hooks.set("insertImageDialog",my_dialog)
    editor1.run();
</script> 

3. pressed the image link

What is the expected output? What do you see instead?
![enter image description here][5]

What version of the product are you using? On what operating system?
N/A

Please provide any additional information below.

I can make it work if commenting out the 
                postProcessing();


inside the linkEnteredCallback function

Original issue reported on code.google.com by gards...@gmail.com on 7 Oct 2011 at 2:47