Changing the size of the tinyMCE rich text editor

Sorry for the double post but actually, that doesn't seem to have worked at all. I'm not sure what happened, but I thought it worked, but it didn't.

The below html is what lithium spits out after tinymce is initialised. I think the reason it worked at the beginning, was it looked like it was using the textarea, while now the textarea is hidden and the iframe is being used instead(?)... I'm not quite sure why this might be.

<div class="message-body-editor">
  <div class="lia-inline-ajax-feedback">
    <div class="AjaxFeedback" id="ajaxFeedback"></div>
  </div>
  <div id="mce_16" class="mce-tinymce ..." hidefocus="1" tabindex="-1" role="application" style="visibility: hidden;...">
    <div id="mce_16-body" class="mce-container-body ...">
      <div id="mce_17" class="mce-toolbar-grp ..." hidefocus="1" tabindex="-1" role="group">
      ...
      </div>
      <div id="mce_26" class="mce-edit-area ..." hidefocus="1" tabindex="-1" role="group" style="border-width: 1px 0px 0px;">
        <iframe id="tinyMceEditor_ifr" src='x-javascript&colon;""' frameborder="0" allowtransparency="true" title="Rich Text Area..." style="width: 100%; height: 250px; display: block;"></iframe>
      </div>
      <div id="mce_27" class="mce-statusbar ..." hidefocus="1" tabindex="-1" role="group" style="...">
      ...
      </div>
    </div>
  </div>
  <textarea class="lia-form-tiny-mce-editor-input lia-message-editor" id="tinyMceEditor" name="tinyMceEditor" aria-hidden="true" style="display: none;"></textarea>
  <div class="lia-inline-ajax-feedback">
    <div class="AjaxFeedback" id="ajaxFeedback"></div>
  </div>
</div>