title: tinymce 4 dropdown list doesn't cover button
body: <p>Tinymce plugin v4 doesn't hide the button for font after clicking on it to select the new font. This happens to all selectbox elements if the plugin is not on the top of the page.</p>
  
  <p>Here is my code and an example.</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  &lt;html&gt;
  &lt;head&gt;
  &lt;title&gt;test tiny mce&lt;/title&gt;
  &lt;script type="text/javascript" src="tinymce.min.js"&gt;&lt;/script&gt;
  &lt;/head&gt;
  &lt;body&gt;
  &lt;button style="width:30%;height:300px"&gt;test&lt;/button&gt;
  &lt;textarea width="50%"&gt;&lt;/textarea&gt;
  &lt;button style="width:30%;height:300px"&gt;test2&lt;/button&gt;
  &lt;script&gt;tinymce.init({
    selector: "textarea",  
    plugins: "paste,lists,code,insertdatetime,preview, textcolor colorpicker, pagebreak",
    menubar: "",
  
    paste_as_text: true,
    paste_word_valid_elements: "b,strong,i,em,h1,h2",
     toolbar: [
      'bold italic underline strikethrough | alignleft aligncenter alignright alignjustify formatselect fontselect fontsizeselect'  , "nonbreaking",
      'paste pastetext | bullist numlist | outdent indent blockquote | undo redo code | insertdatetime preview | forecolor backcolor, textcolor colorpicker',
  
    ],
  
      code_dialog_width: 300,
      code_dialog_height: 300,
      //branding:false,
      statusbar:false,
    //width : 300,
    //max_height : 100
  });&lt;/script&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p><a href="https://i.stack.imgur.com/u3y4E.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/u3y4E.png" alt="enter image description here"></a></p>