How can I reproduce the insertion of math into a figure, as demonstrated in the quick tour video?

Eduardo M M Mendes <[email protected]>
Newsgroups gmane.editors.texmacs.user
Message-ID <[email protected]> 
Hello,

I was watching the quick tour video on the TeXmacs website when I noticed that it's possible to add math to a PDF figure within a figure environment, as demonstrated at 1:06 in the video. Then, I opened TeXmacs and attempted the same with one of my PDF figures, but unfortunately, I was not successful. I didn't even see the red cross cursor when clicking on the math symbol.

What did I miss?

Many thanks,

Ed

P.S. I also attempted the same process with the latest release of Mogan, but the insertion of a PDF file is no longer available. However, it still didn't work with a PNG file either.
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