Adding non-geogebra <iframe> code to Text element
I am creating a Geogebra Book on some Economics topics. In one chapter I have an activity where I have inserted a Text Element and I want to embed HTML <iframe> tags to link to a dynamic non-geogebra chart chart (this one from Our World in Data). To do this I've clicked on the CODE button in the Text editor and pasted in the iframe code like this:
When I close the text box I don't see anything displayed. However, when I edit the text element again I then see the correctly displayed embedded and interactive chartl in editor mode.
But when I close again to see the displayed activity just has a blank page where the external chart should be.
So it seems as if geogebra can display things correctly in editor mode but it somehow gets lost. Does anybody have any suggestions. Am I embedding the HTML iframe code correctly?