hidenodes.cs

protected override void ApplicationStarted(UmbracoApplicationBase umbracoApplication, ApplicationContext applicationContext)
{
    TreeControllerBase.TreeNodesRendering += TreeControllerBase_TreeNodesRendering;
}

private void TreeControllerBase_TreeNodesRendering(TreeControllerBase sender, TreeNodesRenderingEventArgs e)
{
    if (sender.TreeAlias == "content")
    {
        var shared = e.Nodes?.Where(x => x.Name == "Shared").FirstOrDefault();
        if (shared != null)
        {
            e.Nodes.Remove(shared);
        }
    }
}