Abide from version 5.5.2 does not validate hidden fields. However, that also means that the validation does not work for fields in inactive tabs.
Here is an example of some code:
<form data-abide>
<ul class="tabs" data-tab>
<li class="tab-title active"><a href="#panel1">Tab Name</a></li>
<li class="tab-title"><a href="#panel2">Tab Email</a></li>
</ul>
<div class="tabs-content">
<div class="content active" id="panel1">
<div class="name-field">
<label>Your name <small>required</small>
<input type="text" required pattern="[a-zA-Z]+">
</label>
<small class="error">Name is required and must be a string.</small>
</div>
</div>
<div class="content" id="panel2">
<div class="email-field">
<label>Email <small>required</small>
<input type="email" required>
</label>
<small class="error">An email address is required.</small>
</div>
</div>
</div>
<button type="submit">Submit</button>
</form>
<script>
$(document).foundation();
</script>
View it live here: http://jsfiddle.net/1ukfgwqt/ (avoid clicking the second tab before clicking Submit).
Is there another method, besides reverting to 5.5.1 or manually editing Foundation's JS files, to enable validation for hidden fields or correct validation for inactive tabs (pending the resolution of the issue I raised)?