When you have a datagrid which retrieves data over XPATH, the XPath constraint is retained when switching the entity. It is simply validated again for the newly selected entity. However when you have the retrieve activity in a microflow, the XPath constraint is emptied when you change the entity, even if the newly selected entity is a specialization of the previously selected entity.
This is inconsistent, and because of that I often have to cancel changes, re-open the "Retrieve" action in order to copy-paste my XPath constraint. So I would really like the behaviour for microflow retrieves to become the same as for datagrid retrieve via xpath.