title: tinyMCE does not addControl of a specific textarea
body: <p>I am trying to add a textarea and dynamically active it with </p>
  
  <pre><code>tinyMCE.execCommand('mceAddControl', false,'id')
  </code></pre>
  
  <p>I have tried it with other textareas and it works great, but is not working with this specific textarea: </p>
  
  <pre><code>'id_sguidepoint_set-'+index+'-gp_description'
  </code></pre>
  
  <p>Could it be that the name is too big? Or because some of the characters are not valid in tinyMCE?</p>
  
  <p>Here is my tinyMCE initial configuration:</p>
  
  <pre><code>tinyMCE.init({
              mode : "textareas",
              theme : "advanced",
              plugins : "emotions,spellchecker,advhr,insertdatetime,preview,jbimages", 
  
              // Theme options - button# indicated the row# only
              theme_advanced_buttons1 : "newdocument,|,bold,italic,underline,|,justifyleft,justifycenter,justifyright,fontselect,fontsizeselect,formatselect",
              theme_advanced_buttons2 : "cut,copy,paste,|,bullist,numlist,|,outdent,indent,|,undo,redo,|,link,unlink,anchor,jbimages,|,code,preview,|,forecolor,backcolor",
              theme_advanced_buttons3 : "insertdate,inserttime,|,spellchecker,advhr,,removeformat,|,sub,sup,|,charmap,emotions",      
              theme_advanced_toolbar_location : "top",
              theme_advanced_toolbar_align : "left",
              theme_advanced_resizing : false ,
              relative_urls : false
      });
  </code></pre>
  
  <p>and this is the element that I want to activate:</p>
  
  <pre><code>&lt;textarea id="id_sguidepoint_set-3-gp_description" rows="10" cols="40" name="sguidepoint_set-3-gp_description" style="display: none; " aria-hidden="true"&gt;&lt;/textarea&gt;
  </code></pre>
  
  <p>Obviously there are more than one textarea, that is why I have to use an index to iterate through them</p>
  
  <p>Any help will be really appreciated</p>
  
  <p>Thanks in advance</p>