FormBuilderDropdown is not displayed correctly, when readOnly is equal to true

[hsinte]

Everything is fine,when readOnly is Not set to true.

When readOnly is set to true, the value is displayed instead of child.

For example, when readOnly=true, initialValue='1',

I expect to show "apple" but actually show "1".

Map labelValue = Map();
labelValue['apple'] = '1';
labelValue['banana'] = '2';

var fbd = FormBuilderDropdown(
      attribute: 'test',
      initialValue: '1',
      decoration: InputDecoration(
        labelText: 'test',
      ),
      items: labelValue.entries.map((item) {
        return DropdownMenuItem(
          value: item.value,
          child: Text(item.key),
        );
      }).toList(),
      //readOnly: true,
    );

return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('test'),
        ),
        body: Padding(
          padding: const EdgeInsets.all(8.0),
          child: Center(
            child: fbd,
          ),
        ),
      ),
    );