The date widget seems to not have undergone a change in ACS along with the upgrade for ZEN.
Are people using it? At Quest they took a stab at changing it from using tables and it looks much better than in a default 5.3.1 install, but I am not sure if someone put an effort into it before copying over a new version to HEAD.
The following is the resulting HTML code, cutted:
<div class="required-form-row">
<label for="meeting_date" class="form-label">Meeting date: <span>*</span></label>
<!-- date meeting_date begin -->
<input name="meeting_date.format" value="DD Month YYYY" type="hidden">
<label for="meeting_date.day" class="hidden-label">meeting_date day</label>
<select name="meeting_date.day" id="meeting_date.day" onblur="showDayOfTheWeek(meeting, 'meeting_date', 'dayOfTheWeek');">
<option value="" selected="selected">--</option>
<option value="1">01</option>
<option value="31">31</option>
</select> <label for="meeting_date.month" class="hidden-label">meeting_date month</label>
<select name="meeting_date.month" id="meeting_date.month" onblur="showDayOfTheWeek(meeting, 'meeting_date', 'dayOfTheWeek');">
<option value="">--</option>
<option value="1">January</option>
<option value="12">December</option>
</select> <label for="meeting_date.year" class="hidden-label">meeting_date year</label>
<input name="meeting_date.year" size="4" maxlength="4" value="" id="meeting_date.year" onblur="showDayOfTheWeek(meeting, 'meeting_date', 'dayOfTheWeek');" type="text">
<!-- date meeting_date end -->
<span id="dayOfTheWeek"></span>
</div>
