It would be useful o be able to group tables, sort of creating mini models within the overall scheme.
There is already the concept of multiple diagrams, how this is different from what already exists?
This would be useful a large complex database has been imported. You could then create a diagram of all tables and start creating groups (and adding to them) as you explore the database, and move them as a group as you reposition things to make the diagram more usable.
Ok, grouping for moving is one thing, that would be multi select. But in Data Modeler you have the option to create multiple diagrams (for example, "Financing tables", "HR tables", etc., and then you add the desired tables you want to the specific diagram, exactly to organize big databases into smaller chunks.
Note I'm not against adding interesting features, but I also want to avoid to have features which use cases intersect.
I Use the multi select, but being able to name a selection would make it easier to reselect.
How about a slightly different approach - select a group of table and have the option to create a new diagram with them or copy/move them to another diagram?
Ok, this is a nice one!