Recommended way to use an iframe pointing do a list document in Nintex Forms 2016?

Have a look at page viewer control.  it works the way it creates its own iframe

Hi. Yes that was the solution I've came accross. Now I just have to buid a javascript mechanism to choose between the document and related docs or attachments.

By the way, I'm putting bootstrap tabs html inside a text editor, refencing the css and scripts without problems. When I hit sabe in the text editor, it automatically adds target="_blank" to my anchors. Do you know why?

Thanks.  

I'm sorry, I do not follow what you're trying to do.