Custom Widget, multiple File input Errors always returns undefined

[MarcusKuehn]

My Custom Widget builds a DropZone where you can drop multiple Files. When it comes to error handling, i provide the errors to the onChange() but no Error is shown. After some research, i found the ArrayFields.js , there is a handling for Custom Widgets witch does not use onChange but onSelectChange that is always putting undefined in the onChange method. Is this intended?

 this.onSelectChange = (value) => {
            const { onChange, idSchema } = this.props;
            onChange(value, undefined, idSchema && idSchema.$id);
        };

react-jsonschema-form/packages/core/src/components/fields/ArrayField.tsx

Line 421 in 9d1ff6d

onSelectChange = (value: any) => {

How is it possible to show Errors for such an Array, when this is intended?

schema: {
      "type":       "object",
      "required":   [
         "file",
      ],
      "properties": {
         "description": {
            "type":    "string",
            "title":   "Beschreibung",
            "default": "",
         },
         "file":        {
            "type":  "array",
            "title": "Datei",
            "items": {
               "type":   "string",
               "format": "data-url",
            },
         },
         "fileSingle":  {
            "type":   "string",
            "title":  "DateiSingle",
            "format": "data-url",
         },
      },
   }

uiSchema: {
                           "file":       {
                              "ui:widget":  "FileWidget",
                              "ui:options": {
                                 "accept": "application/pdf, image/png",
                              },
                           },
                           "fileSingle": {
                              "ui:widget":  "FileWidget",
                              "ui:options": {
                                 "accept": "application/pdf, image/png",
                              },
                           },
                        }