Just follow this

https://world.episerver.com/blogs/Duong-Nguyen/Dates/2014/1/Country-Region-drop-down-lists-in-All-properties-mode/

Thanks Henrik, so I would have to use DOJO to acheive this. No other way around this, I guess?

No, but that is quite simple dojo so it should not be any problem

Thanks again,

I am getting quite a lot JS errors and the most important one is this

http://localhost:12345/EPiServer/Shell/10.12.2.0/ClientResources/alloy/editors/LocationBlockContainer.js

This is my code to modify meta data

    [EditorDescriptorRegistration(TargetType = typeof(LocationBlock))]
    public class LocationBlockEditorDescriptor : EditorDescriptor
    {
        public override void ModifyMetadata(EPiServer.Shell.ObjectEditing.ExtendedMetadata metadata, IEnumerable<Attribute> attributes)
        {
            base.ModifyMetadata(metadata, attributes);
            metadata.Properties.Cast<ExtendedMetadata>().First().GroupSettings.ClientLayoutClass = "alloy/editors/LocationBlockContainer";
        }
    }

I have started my Empty Alloy project. Now sure where to put these JS files. Any comment on that one?

An explanation of how to create multiple dropdowns with dojo:

https://andersnordby.wordpress.com/2014/10/24/creating-a-custom-property-with-a-dojo-widget/

An explanation of how to create multiple dropdowns with dojo:

https://andersnordby.wordpress.com/2014/10/24/creating-a-custom-property-with-a-dojo-widget/