title: cannot check(select) radio button inside a modal dialog
body: <p>In my page I am using custom modal dialog and inside that modal I am using a form. I have put two radio button inside that form but I cannot check either one.</p>
  
  <pre><code>&lt;div id="user_modal" class="modal modal__bg" role="dialog" aria-hidden="true"&gt;
      &lt;div class="modal__dialog"&gt;
          &lt;div class="modal__content"&gt;
              &lt;h1&gt;User registration&lt;/h1&gt;
  
              &lt;form action="" id="u_register_form"&gt;
  
                  &lt;div class="form-group"&gt;
                    &lt;input type="text" class="form-control" id="fullname" placeholder="Full name" required/&gt;
                  &lt;/div&gt;
  
                  &lt;div class="form-group"&gt;
                      &lt;label class="radio-inline"&gt;&lt;input type="radio" value="w" name="optradio"/&gt;Worker&lt;/label&gt;
                      &lt;label class="radio-inline"&gt;&lt;input type="radio" value="e" name="optradio"/&gt;Engineer&lt;/label&gt;
                  &lt;/div&gt; 
  
                  &lt;div class="form-group"&gt;
                    &lt;input type="text" class="form-control" id="username" required placeholder="Username"&gt;
                  &lt;/div&gt;
  
                  &lt;div class="form-group"&gt;
                    &lt;input type="password" class="form-control" id="u_pwd1" pattern=".{8,}" required placeholder="Password"/&gt;
                  &lt;/div&gt;
  
                  &lt;div class="form-group submit_btn"&gt;
                      &lt;input class="btn btn-success" id="u_register_btn" type="submit" value="SAVE"&gt;
                  &lt;/div&gt;
  
              &lt;/form&gt;
  
              &lt;!-- modal close button --&gt;
              &lt;a href="" class="modal__close demo-close"&gt;
                  &lt;svg class="" viewBox="0 0 24 24"&gt;&lt;path d="M19 6.41l-1.41-1.41-5.59 5.59-5.59-5.59-1.41 1.41 5.59 5.59-5.59 5.59 1.41 1.41 5.59-5.59 5.59 5.59 1.41-1.41-5.59-5.59z"/&gt;&lt;path d="M0 0h24v24h-24z" fill="none"/&gt;&lt;/svg&gt;
              &lt;/a&gt;
  
          &lt;/div&gt;
      &lt;/div&gt;
  &lt;/div&gt;
  </code></pre>