add and use unique to replace controllers if one of the same type comes along.

src/Umbraco.Web.UI.Client/src/core/context-api/consume/context-consumer.controller.ts

@@ -6,6 +6,10 @@ import { UmbControllerHostInterface } from 'src/core/controller/controller-host.
 
 export class UmbContextConsumerController extends UmbContextConsumer<UmbControllerHostInterface> implements UmbControllerInterface {
 
+	public get unique() {
+		return this._contextAlias;
+	}
+
 	constructor(host:UmbControllerHostInterface, contextAlias: string, callback: UmbContextCallback) {
 		super(host, contextAlias, callback);
 		host.addController(this);

src/Umbraco.Web.UI.Client/src/core/context-api/consume/context-consumer.ts

@@ -23,7 +23,7 @@ export class UmbContextConsumer<HostType extends EventTarget = EventTarget> {
 	 * @param {UmbContextCallback} _callback
 	 * @memberof UmbContextConsumer
 	 */
-	constructor(protected host: HostType, private _contextAlias: string, private _callback: UmbContextCallback) {}
+	constructor(protected host: HostType, protected _contextAlias: string, private _callback: UmbContextCallback) {}
 
 
 	private _onResponse = (instance: unknown) => {

src/Umbraco.Web.UI.Client/src/core/context-api/provide/context-provider.controller.ts

@@ -5,6 +5,10 @@ import { UmbControllerHostInterface } from 'src/core/controller/controller-host.
 
 export class UmbContextProviderController extends UmbContextProvider<UmbControllerHostInterface> implements UmbControllerInterface {
 
+	public get unique() {
+		return this._contextAlias;
+	}
+
 	constructor(host:UmbControllerHostInterface, contextAlias: string, instance: unknown) {
 		super(host, contextAlias, instance);
 

src/Umbraco.Web.UI.Client/src/core/context-api/provide/context-provider.ts

@@ -9,8 +9,8 @@ export class UmbContextProvider<HostType extends EventTarget = EventTarget > {
 
 	protected host: HostType;
 
-	private _contextAlias: string;
-	private _instance: unknown;
+	protected _contextAlias: string;
+	#instance: unknown;
 
 	/**
 	 * Creates an instance of UmbContextProvider.
@@ -22,7 +22,7 @@ export class UmbContextProvider<HostType extends EventTarget = EventTarget > {
 	constructor(host: HostType, contextAlias: string, instance: unknown) {
 		this.host = host;
 		this._contextAlias = contextAlias;
-		this._instance = instance;
+		this.#instance = instance;
 	}
 
 	/**
@@ -51,6 +51,6 @@ export class UmbContextProvider<HostType extends EventTarget = EventTarget > {
 		if (event.contextAlias !== this._contextAlias) return;
 
 		event.stopPropagation();
-		event.callback(this._instance);
+		event.callback(this.#instance);
 	};
 }

src/Umbraco.Web.UI.Client/src/core/controller/controller-host.mixin.ts

@@ -45,6 +45,17 @@ export const UmbControllerHostMixin = <T extends HTMLElementConstructor>(superCl
 		 * @param {UmbControllerInterface} ctrl
 		 */
 		addController(ctrl: UmbControllerInterface): void {
+
+			// Check if there is one already with same unique
+			if(ctrl.unique) {
+				this.#controllers.forEach(x => {
+					if(x.unique === ctrl.unique) {
+						debugger;
+						this.removeController(x);
+					}
+				});
+			}
+
 			this.#controllers.push(ctrl);
 			if(this.#attached) {
 				ctrl.hostConnected();

src/Umbraco.Web.UI.Client/src/core/controller/controller.class.ts

@@ -4,8 +4,15 @@ import { UmbControllerInterface } from './controller.interface';
 export abstract class UmbController implements UmbControllerInterface {
 	protected host?: UmbControllerHostInterface;
 
-	constructor(host: UmbControllerHostInterface) {
+
+	private _alias?: string;
+	public get unique() {
+		return this._alias;
+	}
+
+	constructor(host: UmbControllerHostInterface, alias?: string) {
 		this.host = host;
+		this._alias = alias;
 		this.host.addController(this);
 	}
 

src/Umbraco.Web.UI.Client/src/core/controller/controller.interface.ts

@@ -1,4 +1,5 @@
 export interface UmbControllerInterface {
+	get unique(): string | undefined;
 	hostConnected(): void;
 	hostDisconnected(): void;
 	destroy(): void;

src/Umbraco.Web.UI.Client/src/core/element/element.mixin.ts

@@ -12,7 +12,7 @@ interface ResolvedContexts {
 }
 
 export declare class UmbElementMixinInterface extends UmbControllerHostInterface {
-	observe<T>(source: Observable<T>, callback: (_value: T) => void): UmbObserverController<T>;
+	observe<T>(source: Observable<T>, callback: (_value: T) => void, unique?: string): UmbObserverController<T>;
 	provideContext(alias: string, instance: unknown): UmbContextProviderController;
 	consumeContext(alias: string, callback: UmbContextCallback): UmbContextConsumerController;
 	consumeAllContexts(contextAliases: string[], callback: (_instances: ResolvedContexts) => void): void;
@@ -28,8 +28,8 @@ export const UmbElementMixin = <T extends HTMLElementConstructor>(superClass: T)
 		 * @return {UmbObserverController} Reference to a Observer Controller instance
 		 * @memberof UmbElementMixin
 		 */
-		observe<T>(source: Observable<T>, callback: (_value: T) => void): UmbObserverController<T> {
-			return new UmbObserverController<T>(this, source, callback);
+		observe<T>(source: Observable<T>, callback: (_value: T) => void, unique?: string): UmbObserverController<T> {
+			return new UmbObserverController<T>(this, source, callback, unique);
 		}
 
 		/**

src/Umbraco.Web.UI.Client/src/core/observable-api/observer.controller.ts

@@ -6,9 +6,23 @@ import { UmbControllerHostInterface } from 'src/core/controller/controller-host.
 
 export class UmbObserverController<T> extends UmbObserver<T> implements UmbControllerInterface {
 
-	constructor(host:UmbControllerHostInterface, source: Observable<T>, callback: (_value: T) => void) {
+	_alias?: string;
+	public get unique() {
+		return this._alias;
+	}
+
+	constructor(host:UmbControllerHostInterface, source: Observable<T>, callback: (_value: T) => void, alias?: string) {
 		super(source, callback);
-		// TODO: What should happen if source or some? identifier is already present?
+		this._alias = alias;
+
+		// Lets check if controller is already here:
+		/*
+		if (this._subscriptions.has(source)) {
+			const subscription = this._subscriptions.get(source);
+			subscription?.unsubscribe();
+		}
+		*/
+
 		host.addController(this);
 	}
 
@@ -16,4 +30,5 @@ export class UmbObserverController<T> extends UmbObserver<T> implements UmbContr
 		return;
 	}
 
+
 }

src/Umbraco.Web.UI.Client/src/core/observable-api/observer.ts

@@ -3,16 +3,8 @@ import { Observable, Subscription } from 'rxjs';
 export class UmbObserver<T> {
 
 	#subscription!: Subscription;
-	
-	constructor(source: Observable<T>, callback: (_value: T) => void) {
 
-		// TODO: can be transferred to something using alias?
-		/*
-		if (this._subscriptions.has(source)) {
-			const subscription = this._subscriptions.get(source);
-			subscription?.unsubscribe();
-		}
-		*/
+	constructor(source: Observable<T>, callback: (_value: T) => void) {
 
 		this.#subscription = source.subscribe((value) => callback(value));
 	}
@@ -27,4 +19,4 @@ export class UmbObserver<T> {
 		this.#subscription.unsubscribe();
 	}
 
-};
+};

src/Umbraco.Web.UI.Client/src/core/resources/resource.controller.ts

@@ -7,12 +7,13 @@ import { UmbNotificationOptions, UmbNotificationService } from 'src/core/notific
 import { UmbNotificationDefaultData } from 'src/core/notification/layouts/default';
 
 export class UmbResourceController extends UmbController {
+
 	#promise: Promise<any>;
 
 	#notificationService?: UmbNotificationService;
 
-	constructor(host: UmbControllerHostInterface, promise: Promise<any>) {
-		super(host);
+	constructor(host: UmbControllerHostInterface, promise: Promise<any>, alias?: string) {
+		super(host, alias);
 
 		this.#promise = promise;