I have been looking into Bootstrap 4 - beta, however when using .is-invalid with .input-group it doesn't seem to show up.
<link href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0-beta/css/bootstrap.min.css" rel="stylesheet" />
<div class="form-group">
<label for="label">Label</label>
<div class="input-group">
<div class="input-group-addon">
label
</div>
<input type="text" value="" name="label" class="form-control is-invalid">
</div>
<div class="invalid-feedback is-invalid">
<strong>Invalid Label</strong>
</div>
</div>
How are you meant to display an invalid message while using .input-group?
Adding the following CSS works as a workaround, but it seems odd.
.form-group.is-invalid {
.invalid-feedback {
display: block;
}
}

