Magento 1.9 contact form validate required not working

Question

For some reason our select dropdown is not required and does not validate the entry. It already contains the class 'required-entry' for the select.

What am I missing here?

<form action="<?php echo $this->getFormAction(); ?>" id="contactForm" method="post">
    <div class="fieldset">
        <ul class="form-list">
        <h2 class="head">Contactform</h2>    
            <li>
                <div class="field">
                    <label for="titel" class="required"><span><em>*</em><?php echo Mage::helper('contacts')->__('Titel') ?></span></label>
                    <div class="input-box title">
                        <input type="radio" name="titel" id="titeldhr" value="Dhr." checked><label for="titeldhr">Dhr.</label>
                        <input type="radio" name="titel" id="titelmevr" value="Mevr."><label for="titelmevr"> Mevr.</label>
                </div>
                </div>
            </li>
            <li class="fields">
                <div class="field">
                    <label for="name" class="required"><span><em>*</em><?php echo Mage::helper('contacts')->__('Fullname') ?></span></label>
                    <div class="input-box">
                        <input autofocus name="name" id="name" title="<?php echo Mage::helper('contacts')->__('Fullname') ?>" value="<?php echo $this->escapeHtml($this->helper('contacts')->getUserName()) ?>" class="input-text required-entry" type="text" />
                    </div>
                </div>
            </li>
            <li>
                <div class="field">
                    <label for="email" class="required"><span><em>*</em><?php echo Mage::helper('contacts')->__('Emailaddress') ?></span></label>
                    <div class="input-box">
                        <input name="email" id="email" title="<?php echo Mage::helper('contacts')->__('Emailaddress') ?>" value="<?php echo $this->escapeHtml($this->helper('contacts')->getUserEmail()) ?>" class="input-text required-entry validate-email" type="text" />
                    </div>
                </div>
            </li>
            <li>
                <label for="telephone"><span><?php echo Mage::helper('contacts')->__('Phone') ?></span></label>
                <div class="input-box">
                    <input name="telephone" id="telephone" title="<?php echo Mage::helper('contacts')->__('Phone') ?>" value="" class="input-text validate-telephone" type="text" />
                </div>
            </li>
            <li>
                <label for="orderid"><span><?php echo Mage::helper('contacts')->__('Ordernumber') ?></span></label>
                <div class="input-box">
                    <input name="orderid" id="orderid" title="<?php echo Mage::helper('contacts')->__('Ordernumber') ?>" value="" class="input-text validate-telephone" type="text" />
                </div>
            </li>
            <li>
                <label for="dropdown" class="required"><span><em>*</em><?php echo Mage::helper('contacts')->__('Question') ?></span></label>
                <div class="input-box">
                <div class="dropdown required-entry">
                    <select name="dropdown" id="dropdown" class="required-entry validate-select">
                        <option value="" selected><?php echo $this->__('Please Select'); ?></option>
                        <option name="marketing" value="Marketing"><?php echo $this->__('Marketing'); ?></option>
                        <option name="business" value="Business"><?php echo $this->__('Business'); ?></option>
                        </select>
                </div>
            </li>
            <li>
                <div class="field">
                <label for="onderwerp" class="required"><span><em>*</em><?php echo Mage::helper('contacts')->__('Title') ?></span></label>
                <div class="input-box">
                    <input name="onderwerp" id="onderwerp" title="<?php echo Mage::helper('contacts')->__('Title') ?>" value="" class="input-text required-entry" type="text" />
                </div>
                </div>
            </li>
            <li>

            <li>
                <label for="comment" class="required"><span><em>*</em><?php echo Mage::helper('contacts')->__('Comment') ?></span></label>
                <div class="input-box">
                    <textarea name="comment" id="comment" title="<?php echo Mage::helper('contacts')->__('Comment') ?>" class="required-entry input-text" cols="5" rows="3"></textarea>
                </div>
            </li>
            <input type="hidden" name="contact" value="1" />
        </ul>
    </div>
    <?php echo $this->getChildHtml('studioforty9.recaptcha.explicit'); ?>
    <div class="buttons-set">
        <input type="text" name="hideit" id="hideit" value="" style="display:none !important;" />
        <button type="submit" title="<?php echo Mage::helper('contacts')->__('Sent') ?>" class="button"><span><span><?php echo Mage::helper('contacts')->__('Sent') ?></span></span></button>
    </div>
</form>
<script type="text/javascript">
    Validation.defaultOptions.immediate = true;
</script>
<script type="text/javascript">
//<![CDATA[
    var contactForm = new VarienForm('contactForm', true);
//]]>
</script>

Answer 1

Remove required-entry class from <select> and remove selected attribute from <option>

 <select name="dropdown" id="dropdown" class="validate-select">
         <option value=""><?php echo $this->__('Please Select'); ?></option>
         <option name="marketing" value="Marketing"><?php echo $this->__('Marketing'); ?></option>
         <option name="business" value="Business"><?php echo $this->__('Business'); ?></option>
 </select>