Diagram icon in open project review

Hello,
what factor is responsible for the appearance of a specific diagram in the project preview? This is not id.

Currently we simply use the first diagram in the project to create its thumbnail. Feel free to contact me for any questions and wish you have a good day!

I understand that this is the first one created. Not the one with ID 1. Changing the id did nothing when it comes to creating a thumbnail.
Is there any way to list which diagram was created as 1st?

Thanks for replying and I’m sorry that currently we do not support listing the creation order of the diagrams. We may consider to support let user specify which diagram will be use as project thumbnail in future. Feel free to contact me for any questions and wish you have a good day!