title: Problem with FabricJS TextBox can't select and edit value & Layer Index is not working correctly
body: <p><br />
  I have a problem with Fabric Text Box: user can't select TextBox &amp; edit value. And using function <code>canvas.MoveTo</code> to set image of cloud to index 2 &amp; Text Box to index 7, I expect TextBox is above Image, but actually, the Text box is always display behind the cloud image. <br />
  Here is my code</p>
  
  <p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
  <div class="snippet-code">
  <pre class="snippet-code-js lang-js prettyprint-override"><code>var canvasObject = document.getElementById("editorCanvas");
  // set canvas equal size with div
  $(canvasObject).width($("#canvasContainer").width());
  $(canvasObject).height($("#canvasContainer").height());
  
  var canvas = new fabric.Canvas('editorCanvas', {
      backgroundColor: 'white',
      selectionLineWidth: 2,
      width: $("#canvasContainer").width(),
      height: $("#canvasContainer").height()
  });
  
  canvas.setBackgroundImage('https://futushigame.firebaseapp.com/Background.svg', canvas.renderAll.bind(canvas), {
      // Needed to position backgroundImage at 0/0
      originX: 'left',
      originY: 'top'
  });
  
  fabric.Image.fromURL("https://futushigame.firebaseapp.com/group5.svg", function(img) {
      img.left = 0.2;
      img.top = 54.94981;
      canvas.add(img);
      canvas.moveTo(img, 2);
      canvas.renderAll();
  });
  
  var textbox7 = new fabric.Textbox("LITTLE PRINCESS", {
      left: 0,
      top: -14.620352,
      width: 169.598436,
      fontSize: 19.3302,
      fontFamily: 'Nunito-Bold',
      fill: "#000000",
      editable: true,
  });
  textbox7.editable = true;
  canvas.add(textbox7);
  canvas.moveTo(textbox7, 7);
  textbox7.transformMatrix = [1, 0, 0, 1, 64.7895, 169.1073];
  textbox7.setCoords();
  canvas.renderAll();</code></pre>
  <pre class="snippet-code-css lang-css prettyprint-override"><code>#canvasContainer {
    width: 100%;
    height: 100vh;
    background-color: gray;
  }</code></pre>
  <pre class="snippet-code-html lang-html prettyprint-override"><code>&lt;script src="https://code.jquery.com/jquery-3.3.1.js"&gt;&lt;/script&gt;
  &lt;script src="https://cdnjs.cloudflare.com/ajax/libs/fabric.js/2.4.3/fabric.js"&gt;&lt;/script&gt;
  &lt;div id="canvasContainer"&gt;
    &lt;canvas id="editorCanvas"&gt;&lt;/canvas&gt;
  &lt;/div&gt;</code></pre>
  </div>
  </div>
  </p>