I am using 44.0.2403.107
version of Chrome. Try if upgrading the browser helps. If not, I suggest going through the browser setting to see whether there is some kind of security setting that disables the content in iframe elements. Also, you can check whether this comes from a plugin and disable it. Further, you can test on a different machine with Chrome and see whether the results are the same.
As you can see the HTML dedicated for the content area is rendered as HTML, but it is up to the browser to show it.
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