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Do any errors show in your browser's Javascript console? If so, what precise errors?

What does the browser network activity debug tab show exactly? For example, looking at the HTTP request opened when you click the tab may show an error message in there, a hung request, or no request at all.

Or, where can we go to reproduce the problem on your server if you're not show how to do the above?
(you didn't post a URL)

This is almost certainly a configuration/server issue, as there have been no other reports regarding an issue such as the above. For example, perhaps some server permissions were changed during upgrade.

Hello,

We received your email response through with a screenshot of the Javascript error. Thank you, this helps a lot.

Please reply direct on the tracker though, as email replies will just go through to a single person.

It looks like it could be a problem just affecting Internet Explorer. I am going to run some tests soon.

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Automated response: Provide stronger XML parsing fallback on AJAX, for IE

If there is some kind of XHTML error, perhaps caused by a server-side failure, Composr is supposed to revert to HTML rendering. However IE throws a fatal error, unlike other browsers. This hotfix will workaround that.

I suspect the above hotfix will only result in you now seeing an error message stating your true problem.

I was not able to reproduce, except when I intentionally corrupted the HTML for the edit tab. I therefore made a hotfix that handles corrupt HTML.

If you get to see a true error message now and it is not a cause that you can pin down to a configuration issue on your end, please open a separate ticket.

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