Its not possible to use attribute type 'url' as alias in relation properties

[zonky2]

Its not possible to use attribute type 'url' as alias in relation properties

Its not possible so save an item, because we have an error from compare widgetToValue and valueToWidget...

Before the problem can be solved, a new interface must be built into the core and the corresponding implementation built into tags.

MetaModels/core#904
https://github.com/MetaModels/core/compare/feature-aliasaware

There is already a corresponding branch for select

https://github.com/MetaModels/attribute_select/tree/feature-aliasaware

current: "known limitation"