Why select_tag displays only one column? <p>I have the following <strong>select_tag</strong> in my view:</p> <pre><code> &lt;%= select_tag :users, options_from_collection_for_select(@users, 'id','firstname' , 'lastname') %&gt;&lt;/p&gt;&lt;/br&gt; </code></pre> <p>I want to display the firstname and lastname in the select_tag, but it always displays the first parameter after the <strong>'id'</strong> in this case the firstname. </p> <p>What I'm doing wrong?</p>