Hello Dmitry
Thank you very much for the detailed explanation and your suggested alternate solution and code. I prefer a less exotic solution and will therefore first try to pass the necessary attribute values to the views before they are opened and call the setItems() method from within a separate new method after the onInit() handler has been called but before the view’s InstanceContainer is wired to the entity attributes, instead of calling setItems() in the onBeforeShow() handler.
I have used this approach before, noted here: https://forum.jmix.io/t/jmix-2-x-x-opening-dialog-windows-documentation-additional-information-needed/4417, and though it will require considerable extra work, it will be a standard documented approach.
Best regards
Chris