title: Creating a handler to increase font size
body: <p>I am working on a text app, which includes a button to increase text size of selected text in a field.</p>
  
  <p>Below is the handler I am using, it works fine when all the selectedText is currently the same size. If some of the text is a different size, the handler returns this error: </p>
  
  <blockquote>
    <p>execution error at line 42 (Operators +: error in left operand), char
    68</p>
  </blockquote>
  
  <p>The handler:</p>
  
  <pre><code>on txtSizeUp
       set the textSize of selectedText to the textSize of selectedText + 2
  end txtSizeUp
  </code></pre>
  
  <p>WHat do I need to do to change the size regardless of difference?</p>