validateToNameTag = (element, model, flatTree) => {
  const { controlledTags } = model.properties;

  if (!element.toname) return null;

  const names = element.toname.split(","); // for pairwise

  for (const name of names) {
    // Find referenced tag in the tree
    const controlledTag = flatTree.find((item) => item.name === name);

    if (controlledTag === undefined) {
      return errorBuilder.tagNotFound(model.name, "toname", name);
    }

    if (controlledTags && controlledTags.validate(controlledTag.tagName).length) {
      return errorBuilder.tagUnsupported(model.name, "toname", controlledTag.tagName, controlledTags);
    }
  }

  return null;
}
Validates toName attribute
Checks that connected tag is existing tag, it present in the tree
and can be controlled by current Object Tag
@param {Object} element
@param {Object} model
@param {Object[]} flatTree