Input-group doesn't work with class="form-control k-textbox"

[kakone]

With the new bootstrap 4.0 input-group, the addon is not on the same line that the input when your add the classes form-control and k-textbox. https://dojo.telerik.com/@kakone/ocAxEC

<div class="input-group">
  <div class="input-group-prepend">
    <span class="input-group-text">
      <span class="k-icon k-i-user"></span>
    </span>
  </div>
  <input placeholder="Username" type="text" class="form-control k-textbox" />
</div>

[gyoshev]

This problem is resolved in the latest versions of the theme package. Here is the updated plunker.