Angular 2 RC6 - "sidebar" is not a known element
<p>I just updated to RC6 and have trouble with the following error:</p>

<blockquote>
  <p>zone.min.js:1 Unhandled Promise rejection: Template parse errors:
  'sidebar' is not a known element:
  1. If 'sidebar' is an Angular component, then verify that it is part of this module.
  2. If 'sidebar' is a Web Component then add "CUSTOM_ELEMENTS_SCHEMA" to the '@NgModule.schema' of this component to suppress this message. ("</p>
</blockquote>



<p><code>sidebar</code> isn't a component. Just a html-tag i am using in one of my templates. They look like this:</p>

<pre><code>...
&lt;sidebar class="main-nav"&gt;
    ...
&lt;/sidebar&gt;
...
</code></pre>

<p>I tried updating my NgModule AppModule with <code>CUSTOM_ELEMENTS_SCHEMA</code> like this:</p>

<pre><code>@NgModule({
    declarations: [...],
    providers: [...],
    imports: [BrowserModule, routing, HttpModule, FormsModule, TranslateModule.forRoot()],
    bootstrap: [AppComponent],
    schemas: [ CUSTOM_ELEMENTS_SCHEMA ]
})
export class AppModule { }
</code></pre>

<p>But that doesn't seem to do anything.</p>

<p>Does anyone haven an idea or a hint?</p>