diff --git a/frontend/app/framework/angular/routers/router-2-state.spec.ts b/frontend/app/framework/angular/routers/router-2-state.spec.ts
index 1e38600dd..bd4f80602 100644
--- a/frontend/app/framework/angular/routers/router-2-state.spec.ts
+++ b/frontend/app/framework/angular/routers/router-2-state.spec.ts
@@ -307,13 +307,28 @@ describe('Router2State', () => {
 
             routerQueryParams.next({
                 key1: 'hello',
-                key2: 'squidex',
+                key2: 'cms',
                 key3: '!'
             });
 
             expect(invoked).toEqual(2);
         });
 
+        it('Should not sync again when no state as changed', () => {
+            routerQueryParams.next({
+                key1: 'hello',
+                key2: 'squidex'
+            });
+
+            routerQueryParams.next({
+                key1: 'hello',
+                key2: 'squidex',
+                key3: '!'
+            });
+
+            expect(invoked).toEqual(1);
+        });
+
         it('Should reset other values when synced from route', () => {
             state.next({ other: 123 });
 
diff --git a/frontend/app/framework/angular/routers/router-2-state.ts b/frontend/app/framework/angular/routers/router-2-state.ts
index eeee03ec6..0e934f73f 100644
--- a/frontend/app/framework/angular/routers/router-2-state.ts
+++ b/frontend/app/framework/angular/routers/router-2-state.ts
@@ -299,10 +299,10 @@ export class Router2StateMap<T extends object> implements StateSynchronizerMap<T
             update[key] = this.state.snapshot[key];
         }
 
-        this.state.resetState(update);
-
-        for (const action of this.syncDone) {
-            action();
+        if (this.state.resetState(update)) {
+            for (const action of this.syncDone) {
+                action();
+            }
         }
     }
 
@@ -344,7 +344,7 @@ function cleanupParams(query: Params) {
         if (query.hasOwnProperty(key)) {
             const value = query[key];
 
-            if (Types.isNull(value) || Types.isUndefined(key)) {
+            if (Types.isNull(value) || Types.isUndefined(value)) {
                 delete query[key];
             }
         }
diff --git a/frontend/app/framework/state.spec.ts b/frontend/app/framework/state.spec.ts
new file mode 100644
index 000000000..2b56a3f25
--- /dev/null
+++ b/frontend/app/framework/state.spec.ts
@@ -0,0 +1,72 @@
+/*
+ * Squidex Headless CMS
+ *
+ * @license
+ * Copyright (c) Squidex UG (haftungsbeschränkt). All rights reserved.
+ */
+
+import { State } from './state';
+
+describe('State', () => {
+    let state: State<any>;
+
+    beforeEach(() => {
+        state = new State<any>({});
+    });
+
+    it('should update state with new value', () => {
+        let updateCount = 0;
+
+        state.changes.subscribe(() => {
+            updateCount++;
+        });
+
+        const updated = state.next({ value: 1 });
+
+        expect(updateCount).toEqual(2);
+        expect(updated).toBeTruthy();
+    });
+
+    it('should reset state with new value', () => {
+        let updateCount = 0;
+
+        state.changes.subscribe(() => {
+            updateCount++;
+        });
+
+        const updated = state.resetState({ value: 1 });
+
+        expect(updateCount).toEqual(2);
+        expect(updated).toBeTruthy();
+    });
+
+    it('should not update state when nothing changed', () => {
+        let updateCount = 0;
+
+        state.changes.subscribe(() => {
+            updateCount++;
+        });
+
+        state.next({ value: 1 });
+
+        const updated = state.next({ value: 1 });
+
+        expect(updateCount).toEqual(2);
+        expect(updated).toBeFalsy();
+    });
+
+    it('should not reset state when nothing changed', () => {
+        let updateCount = 0;
+
+        state.changes.subscribe(() => {
+            updateCount++;
+        });
+
+        state.resetState({ value: 1 });
+
+        const updated = state.resetState({ value: 1 });
+
+        expect(updateCount).toEqual(2);
+        expect(updated).toBeFalsy();
+    });
+});
\ No newline at end of file
diff --git a/frontend/app/framework/state.ts b/frontend/app/framework/state.ts
index 5280f9e75..d62f22e1f 100644
--- a/frontend/app/framework/state.ts
+++ b/frontend/app/framework/state.ts
@@ -164,7 +164,6 @@ export class ResultSet<T> {
 
 export class State<T extends {}> {
     private readonly state: BehaviorSubject<Readonly<T>>;
-    private readonly initialState: Readonly<T>;
 
     public get changes(): Observable<Readonly<T>> {
         return this.state;
@@ -185,39 +184,54 @@ export class State<T extends {}> {
     }
 
     public projectFrom2<M, N, O>(lhs: Observable<M>, rhs: Observable<N>, project: (l: M, r: N) => O, compare?: (x: O, y: O) => boolean) {
-        return combineLatest(lhs, rhs, (x, y) => project(x, y)).pipe(
-            distinctUntilChanged(compare), shareReplay(1));
+        return combineLatest([lhs, rhs]).pipe(
+            map(([x, y]) => project(x, y)), distinctUntilChanged(compare), shareReplay(1));
     }
 
-    constructor(state: Readonly<T>) {
-        this.initialState = state;
-
-        this.state = new BehaviorSubject(state);
+    constructor(
+        private readonly initialState: Readonly<T>
+    ) {
+        this.state = new BehaviorSubject(initialState);
     }
 
     public resetState(update?: ((v: T) => Readonly<T>) | Partial<T>) {
-        let newState = this.initialState;
+        return this.updateState(this.initialState, update);
+    }
+
+    public next(update: ((v: T) => Readonly<T>) | Partial<T>) {
+        return this.updateState(this.state.value, update);
+    }
+
+    private updateState(state: T, update?: ((v: T) => Readonly<T>) | Partial<T>) {
+        let newState = state;
 
         if (update) {
             if (Types.isFunction(update)) {
-                newState = update(this.initialState);
+                newState = update(state);
             } else {
-                newState = { ...this.initialState, ...update };
+                newState = { ...state, ...update };
             }
         }
 
-        this.state.next(newState);
-    }
+        let isChanged = false;
 
-    public next(update: ((v: T) => Readonly<T>) | Partial<T>) {
-        let newState: T;
+        const newKeys = Object.keys(newState);
 
-        if (Types.isFunction(update)) {
-            newState = update(this.state.value);
+        if (newKeys.length !== Object.keys(this.snapshot).length) {
+            isChanged = true;
         } else {
-            newState = { ...this.state.value, ...update };
+            for (const key of newKeys) {
+                if (newState[key] !== this.snapshot[key]) {
+                    isChanged = true;
+                    break;
+                }
+            }
+        }
+
+        if (isChanged) {
+            this.state.next(newState);
         }
 
-        this.state.next(newState);
+        return isChanged;
     }
 }
\ No newline at end of file
diff --git a/frontend/app/framework/utils/types.ts b/frontend/app/framework/utils/types.ts
index 86dd9a830..65d1cccf7 100644
--- a/frontend/app/framework/utils/types.ts
+++ b/frontend/app/framework/utils/types.ts
@@ -162,15 +162,15 @@ export module Types {
 
             return true;
         } else if (Types.isObject(lhs) && Types.isObject(rhs)) {
-            if (Object.keys(lhs).length !== Object.keys(rhs).length) {
+            const lhsKeys = Object.keys(lhs);
+
+            if (lhsKeys.length !== Object.keys(rhs).length) {
                 return false;
             }
 
-            for (const key in lhs) {
-                if (lhs.hasOwnProperty(key)) {
-                    if (!equals(lhs[key], rhs[key], lazyString)) {
-                        return false;
-                    }
+            for (const key of lhsKeys) {
+                if (!equals(lhs[key], rhs[key], lazyString)) {
+                    return false;
                 }
             }