draw.io Desktop Windows - How to edit an inserted Mermaid diagram?

(searched for draw.io mermaid diagram edit before posting)

I'd like to create and maintain shapes with draw.io desktop (Windows) using Mermaid syntax.

I followed the guide at https://www.drawio.com/blog/mermaid-diagrams and was able to insert a Mermaid diagram. Now I would like to edit that shape.

The blog post says:

To see the Mermaid code for any of the diagrams inserted in this way, select the shape, then press Enter. You can make changes to the code here, then click Apply to update the diagram on the drawing canvas.

That does not work for me. When I select an element and press Enter I just get the Text properties dialog box. Tried this in the web client and diagrams.net and same result.

Is there some way I can see and edit the Mermaid code I used to create a set of shapes using Draw.io Desktop?

When inserting a Mermaid diagram you have to set the type to "Image", if you use the default "Diagram" then the Mermaid diagram is transformed to a regular draw.io diagram, and you can no longer edit the original code.