Node size problem when layouting in Sirius 7.6

[Greglar4]

Hello,

I maintain an Eclipse RCP application that uses Sirius diagrams, and we are in the process of upgrading to Eclipse 2026-06 and Sirius 7.6. We are upgrading from Eclipse 2025-12 and Sirius 7.4.14.

We have noticed that after the upgrade, when layouting one of our diagrams, some of the nodes are resized to larger than needed.

This is what they look like after a layout:

When they used to look something like this:

Also, if after the layout and expansion of the node, you resize the node to the right just at little bit, it snaps back to how it looks in the second picture.

Additionally, this only seems to happen for diagrams of models that were made in a previous version and imported into the new one. If you create a completely new model and diagram, and create the nodes there, the layout does not do this.

Here is our odesign definition of the node where this happens:

ControlInstance has children presentation set to Vertical Stack, and Description has children presentation as List. It seems that only the top level container ControlInstance is getting expanded, because that is what is light purple.

I looked at the ELK changes in 0.9.1 and the only thing I really saw there was this change https://github.com/eclipse-elk/elk/pull/997/changes#diff-8a78e7364c15e36880dd284382a7da489838b748cb00d1ae8f847bf8ab359256

So I tried to set omit micro node layout to true to see if it was this change that caused it, but it still happens, so I don't think it is the ELK change.

Any ideas for what could be going wrong?

Thanks for your time,

Greg

[lredor]

Hi Greg,

I confirm that I would also rule out the ELK hypothesis based on the symptoms you describe.

I rather suspect that some changes were made around the handling of “Vertical Stack” containers, and that these changes did not properly take existing diagrams into account. At first glance, a migration participant should probably have been added to handle this case.

Would it be possible for you to provide a reproducible example? This would help us analyse the root cause of the issue.

Best regards,
Laurent