DynamicModule[{countries = SortBy[#["Name"] &]@RandomEntity["Country", 30]},
 Manipulate[
  EntityValue[country, prop],
  {{country, First@countries, "Country"}, countries},
  {{prop, "Flag", "Property"}, CanonicalName@EntityProperties["Country"]},
  SynchronousInitialization -> False,
  SynchronousUpdating -> False
  ],
 SynchronousInitialization -> False
 ]