Reuse Dropdown as much as possible in Lookup

[mvorisek]

This is a feature request to reuse Dropdown as much as possible in Lookup.

I understand that in the future that Lookup can be more than simple dropdown so I propose not extending Dropdown directly but reusing the the Dropdown component as much as possible. Currently lot of the base code is shared which is hard to maintain.

[ibelar]

Actually, DropDown and Lookup are both extending Input.
In fact Lookup should be an extension of DropDown. They use the same Fomantic-Ui dropdown module at their base but Lookup use the api configuration of the module to perform server query.

[mvorisek]

In fact Lookup should be an extension of DropDown.

I am 100% ok with that. I proposed to wrap it as in the feature Lookup (at least from its name) can be much richer UI element like element with preview of the linked/lookuped value etc.

[romaninsh]

we might have some functionality duplication - similarly to Modal and jsModal - there are some differences and possible that certain things will be discontinued and removed later on. Refactoring is not a huge priority and probably should wait until we've done with atk4/data#375

[mvorisek]

also reuse it in Multiline, prerender it /wo value for vue