HTML Tags that are supposed to be supported not working

[Woodpecker]

I am trying to embed some raw HTML as JSON in a side panel of my app. I found a site with the supported HTML tags, but none of them (or at least most of them) are not working. 

Below is a simple html that I want to embed. 

And this is the result. Not quite what I would expect. 

While I can embed <a href="some_url">, it always opens in the same window. Seems like target=_blank doesn't work either. 

If I want to use <a> in order to jump down to a certain line (eg.

<a href="#someId"></a>

<div id="someId"></div>

), the app will throw the following error:

I am pretty clueless what I'm doing wrong. Even the examples provided by ESRI in the right hand side panel are not yielding the results I would expect.

Any ideas?