Only one instance can be ran at the same time so removing the feature.

Author: Nicolas Garnier

README.md

@@ -269,16 +269,6 @@ import './firebaseui-overrides.global.css'; // Import globally.
 If you would like to see an example of styling, have a look at the [example app](./example).
 
 
-## Using multiple instances
-
-In the case where you would need to load multiple instances of `FirebaseAuth` at the same time you need to set them up with a different ID using the `elementId` attribute. For instance:
-
-```js
-<StyledFirebaseAuth elementId="auth_1" uiConfig={this.uiConfig} firebaseAuth={firebase.auth()}/>
-<StyledFirebaseAuth elementId="auth_2" uiConfig={this.otherUiConfig} firebaseAuth={firebase.auth()}/>
-```
-
-
 ## Contributing
 
 We'd love that you contribute to the project. Before doing so please read our [Contributor guide](CONTRIBUTING.md).

src/FirebaseAuth.jsx

@@ -35,7 +35,6 @@ export default class FirebaseAuth extends React.Component {
 
     this.uiConfig = props.uiConfig;
     this.firebaseAuth = props.firebaseAuth;
-    this.elementId = props.elementId || ELEMENT_ID;
     this.className = props.className;
   }
 
@@ -75,9 +74,6 @@ export default class FirebaseAuth extends React.Component {
     uiConfig: Object,
     // The Firebase App auth instance to use.
     firebaseAuth: Object,
-    // The ID of the underlying container that we'll generate.
-    // Use this if you use more than one instance at a time in your app.
-    elementId?: String,
     // Callback that will be passed the FirebaseUi instance before it is
     // started. This allows access to certain configuration options such as
     // disableAutoSignIn().
@@ -90,7 +86,7 @@ export default class FirebaseAuth extends React.Component {
    */
   render() {
     return (
-      <div className={this.className} id={this.elementId}/>
+      <div className={this.className} id={ELEMENT_ID}/>
     );
   }
 }