no error message when creating an item with no host

(1) When creating an item, it is possible to select no host. It would be nice if it would not be allowed (i.e., there would be no "Empty" button in the popup). It would also be nice if an error message would appear when trying to save such item.

(2) Click on an existing item, then click "Create item". In the provided item form no host is selected. It would be nice if the selected host would be the same as for the previously viewed item.