Track by improvement.

src/Squidex/app/features/content/pages/contents/contents-page.component.html

@@ -122,7 +122,7 @@
                 <div sqxIgnoreScrollbar>
                     <table class="table table-items table-fixed" *ngIf="contentItems" >
                         <tbody *ngIf="!isReadOnly">
-                            <ng-template ngFor let-content [ngForOf]="contentItems">
+                            <ng-template ngFor let-content [ngForOf]="contentItems" [ngForTrackBy]="trackBy">
                                 <tr [sqxContent]="content" [routerLink]="[content.id]" routerLinkActive="active"
                                     [language]="languageSelected"
                                     [schemaFields]="contentFields"

src/Squidex/app/features/content/pages/contents/contents-page.component.ts

@@ -361,6 +361,10 @@ export class ContentsPageComponent implements OnDestroy, OnInit {
         this.ctx.bus.emit(new ContentRemoved(content));
     }
 
+    public trackBy(content: ContentDto): string {
+        return content.id;
+    }
+
     private resetContents() {
         this.contentItems = ImmutableArray.empty<ContentDto>();
         this.contentsQuery = '';