function injectOneWorkspace() {
  const elem = document.getElementById('blockly2');
  elem.parentElement.removeChild(elem);

  const options = {
    toolbox: toolboxCategories,
  };
  workspace1 = Blockly.inject('blockly1', options);

  workspace1.addChangeListener(
    createSerializationListener(workspace1, 'save1'),
  );

  document
    .getElementById('load')
    .addEventListener('click', () => loadWorkspace());
}
Injects one workspace with undo and redo enabled.