Change filepicker icon and other setting

Please show me your code and the contents of your gcs.js file

it does not allow me to copy long text
can i remove the icon totally
or make it refer to the one provided by you

I have just worked with a coworker on a separate machine. Using this HTML (just a slight rearrangement or yours) and a gcs.js file with the exact contents of the Github gist I sent you will work.

<!DOCTYPE html>
<html>
<head>
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>GoCloudStorageManager test</title>

  <script src="https://cdnjs.cloudflare.com/ajax/libs/gojs/1.8.29/go-debug.js"></script>

  <script src="gcs.js"></script>

  <script>
    function init() {
      var $ = go.GraphObject.make;
      myDiagram = $(go.Diagram, "myDiagramDiv",  {
                    initialContentAlignment: go.Spot.Center,  // center the content
                    "undoManager.isEnabled": true  // enable undo & redo
                });

      myDiagram.nodeTemplate =
        $(go.Node, "Auto",  // the Shape will go around the TextBlock
        new go.Binding("location", "loc", go.Point.parse).makeTwoWay(go.Point.stringify),
          $(go.Shape, "RoundedRectangle", { strokeWidth: 0 },
            // Shape.fill is bound to Node.data.color
            new go.Binding("fill", "color")),
          $(go.TextBlock,
            { margin: 8 },  // some room around the text
            new go.Binding("text", "key"))
        );

      // create the model data that will be represented by Nodes and Links
      myDiagram.model = new go.GraphLinksModel(
      [
        { key: "Alpha", color: "lightblue" },
        { key: "Beta", color: "orange" },
        { key: "Gamma", color: "lightgreen" },
        { key: "Delta", color: "pink" }
      ],
      [
        { from: "Alpha", to: "Beta" },
        { from: "Alpha", to: "Gamma" },
        { from: "Beta", to: "Beta" },
        { from: "Gamma", to: "Delta" },
        { from: "Delta", to: "Alpha" }
      ]);

      defaultModel = myDiagram.model.toJson();

      // update the title on page to reflect newly loaded diagram title TODO

      /*
      * Promise handler for core functions
      * @param {String} action Accepted values: Load, Delete, New, Save
      */
      var handlePromise = function (action) {
          switch (action) {
          case 'Load': gls.loadWithUI().then(function (fileData) {
              handleFileData(action, fileData);
              }); break;
              case 'SaveAs': gls.saveWithUI().then(function (fileData){
                  handleFileData(action, fileData);
              }); break;
          }
      }

      gls = new gcs.GoLocalStorage(myDiagram,defaultModel,"../iconsFolder/");
    }

  </script>
</head>
<body onload="init()">
  <button id="openButton" onclick="handlePromise('Load')">Load </button>
  <button id="saveButton" onclick="handlePromise('SaveAs')">Save As</button>
  <h3 id="currentFile">Untitled </h3>
  <div>
      <h4>Diagram 1</h4>
      <div id="myDiagramDiv" style="height: 300px; width: 300px; background-color: lightgray;"></div>
  </div>
</body>