Set errorClass in Form-Fields

[ha75]

How to set an error class to any form field if it is not valid? I tried to add errorClass e.g. in Partials/Fields/Username.html

<femanager:form.textfield
		id="femanager_field_username"
		property="username"
		class="form-control"
		errorClass="form-control"
		additionalAttributes="{femanager:Validation.FormValidationData(settings:settings,fieldName:'username')}" />

However, this is not working.

[spoonerWeb]

I can confirm this. Neither with client validation (JS writes error as class) nor server validation (no class was added).