title: Tab Doesn't Enter with .select2
body: <p>If a user creates a custom option and then clicks tab then that custom option isn't entered.</p>
  
  <p>The user has to hit enter and then tab if he wants to move onto the next element in the form, which I'd like to reduce the unnecessary step of hitting enter first if possible.</p>
  
  <pre><code>&lt;%= simple_form_for(@lifetime, html: { data: { modal: true } }) do |f| %&gt; 
  
    &lt;%= f.grouped_collection_select(:name, @collection, :last, :first, :to_s, :to_s, include_blank: true) %&gt;
  
  &lt;% end %&gt;
  
  &lt;script&gt;
    $('#lifetime_name').select2({
      placeholder: "Enter Challenge",
      theme: "bootstrap",
      allowClear: false,
      tags: true,
      multiple: false,
    });
  &lt;/script&gt;
  </code></pre>
  
  <p>So in other words, if a user writes in a custom option, how can we make tab mean to "enter and move onto next element"? If the user chooses a default option then this problem doesn't exist, but in most cases users will want to create their own custom option.</p>