gridstack.js issue base

Use this as a base for examples for gridstack.js issues.

by ironvd

HTML

<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/gridstack@10.0.0/dist/gridstack.min.css">
<script src="https://cdn.jsdelivr.net/npm/gridstack@10.0.0/dist/gridstack-all.js"></script>

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <title>Advance Nested grids demo</title>
  <link rel="stylesheet" href="https://gridstackjs.com/demo/demo.css"/>
  <link rel="stylesheet" href="https://gridstackjs.com/node_modules/gridstack/dist/gridstack-extra.min.css"/>
  <!-- test using CSS rather than minRow -->
  <style type="text/css">
    .container-fluid > .grid-stack { min-height: 250px}
  </style>
  <script src="https://gridstackjs.com/node_modules/gridstack/dist/gridstack-all.js"></script>
</head>
<body>
  <div class="container-fluid">
    <h1>Advanced Nested grids demo</h1>
    <a class="btn btn-primary" onClick="save(false, false)" href="#">Save layout no content</a>
    <br><br>
    <!-- grid will be added here -->
  </div>
  <p>Output</p>
  <textarea id="saved" style="width:100%; height:200px;"></textarea>
  <script type="text/javascript">
    
    let subOptions = {
      cellHeight: 50, // should be 50 - top/bottom
      column: 'auto', // size to match container. make sure to include gridstack-extra.min.css
      acceptWidgets: true, // will accept .grid-stack-item by default
      margin: 5,
      subGridDynamic: true, // make it recursive for all future sub-grids
    };
    let options = { // main grid options
      cellHeight: 50,
      margin: 5,
      minRow: 2, // don't collapse when empty
      acceptWidgets: true,
      subGridOpts: subOptions,
      subGridDynamic: true, // v7 api to create sub-grids on the fly
      children: [
        {
        	x:0, y:0, w:2, h:4, id: 'sub0',
          subGridOpts: {
        		...subOptions,
            children: [
            	{x:0, y:0, content: 1},
             ...