If you are using the shady dom (web components lite, rather than the low perf full polyfill), the library requires you to do dom manipulation through the polymer local DOM API. [0]<p>That means without shimming other libraries, polymer is incompatible with any other libraries you might use to manipulate the DOM. For example, you can&#x27;t easily mix angular, react, or ember templates with some polymer elements, because (e.g.,) angular&#x27;s ng-if directive doesn&#x27;t use polymer.dom to inject created nodes.<p>This is currently my biggest beef with polymer. Someday, webcomponents will be great, principally due to composability and portability. Just plug the one component you need in to your extant work. But for now, that promise is not quite realized.<p>[0]: <a href="https:&#x2F;&#x2F;www.polymer-project.org&#x2F;1.0&#x2F;docs&#x2F;devguide&#x2F;local-dom.html#dom-api" rel="nofollow">https:&#x2F;&#x2F;www.polymer-project.org&#x2F;1.0&#x2F;docs&#x2F;devguide&#x2F;local-dom....</a>