Enhancement
When editing a (grid) table component, you can define your own calculated columns, among other things. You can select such columns as standard columns, but unfortunately not as ID columns. However, this is desirable.
In the XML configuration of the component, you can select such columns as ID columns, but if you then configure this component in-app again, the ID column set manually in this way is reset.
Test
Create a table (e.g. of type test.transient:Row). Define your own calculated column. If you now select the ID column option for column configurations, the newly defined calculated column should now be available as an option.