Want to create a UML diagram, draw.io power up seems ideal
Create card - new power up - draw.io
Start creating the diagram and at the bottom, the status cycles flashing (perhaps) saving / deleting
In trello, the card has hundreds of comments ... I deleted xyz
So I tried linking draw.io to Google Drive, created a diagram on drive, created new card, added draw.io power up, add attachment, find saved drawing -> load
Error message saying not a valid document.
What **is** the right way to use draw.io in this case?