anchor.diff:        });
       }
       if (widget.onFileSelected != null) {
  -      widget.onFileSelected(file);
  -    }
  -  }
  -}
  -
  -Future<DevToolsJsonFile> importFileFromPicker({
  -  @required List<String> acceptedTypes,
  +      widget.onFileSelected!(file);
  +    }
  +  }
  +}
  +
  +Future<DevToolsJsonFile?> importFileFromPicker({
  +  required List<String> acceptedTypes,
   }) async {
     final acceptedTypeGroups = [XTypeGroup(extensions: acceptedTypes)];
     final file = await openFile(acceptedTypeGroups: acceptedTypeGroups);
  
positive.code:             importedFile?.path ?? 'No File Selected',
              overflow: TextOverflow.ellipsis,
              style: TextStyle(
                color: Theme.of(context).textTheme.headline1.color,
              ),
              textAlign: TextAlign.left,
            ),
  
negative.code:           children: [
              ElevatedButton(
                onPressed: importedFile != null
                    ? () => widget.onAction!(importedFile!)
                    : null,
                child: MaterialIconLabel(
                  label: widget.actionText,
  