Correct handling of duplicates.

src/Squidex/Areas/Api/Controllers/Assets/AssetsController.cs

@@ -179,7 +179,10 @@ namespace Squidex.Areas.Api.Controllers.Assets
 
             var command = new CreateAsset { File = assetFile };
 
-            var response = await InvokeCommandAsync(app, command);
+            var context = await CommandBus.PublishAsync(command);
+
+            var result = context.Result<AssetCreatedResult>();
+            var response = AssetDto.FromAsset(result.Asset, this, app, result.IsDuplicate);
 
             return CreatedAtAction(nameof(GetAsset), new { app, id = response.Id }, response);
         }

src/Squidex/app/shared/components/assets-list.component.ts

@@ -5,7 +5,7 @@
  * Copyright (c) Squidex UG (haftungsbeschränkt). All rights reserved.
  */
 
-import { ChangeDetectionStrategy, Component, EventEmitter, Input, Output } from '@angular/core';
+import { ChangeDetectionStrategy, ChangeDetectorRef, Component, EventEmitter, Input, Output } from '@angular/core';
 import { onErrorResumeNext } from 'rxjs/operators';
 
 import {
@@ -38,11 +38,24 @@ export class AssetsListComponent {
     @Output()
     public select = new EventEmitter<AssetDto>();
 
+    constructor(
+        private readonly changeDetector: ChangeDetectorRef
+    ) {
+    }
+
     public add(file: File, asset: AssetDto) {
+        if (asset.isDuplicate) {
+            setTimeout(() => {
+                this.newFiles = this.newFiles.remove(file);
+
+                this.changeDetector.detectChanges();
+            }, 2000);
+        } else {
             this.newFiles = this.newFiles.remove(file);
 
             this.state.add(asset);
         }
+    }
 
     public search() {
         this.state.load().pipe(onErrorResumeNext()).subscribe();

src/Squidex/app/shared/services/assets.service.ts

@@ -43,6 +43,10 @@ export class AssetDto {
     public readonly canUpdate: boolean;
     public readonly canUpload: boolean;
 
+    public get isDuplicate() {
+        return this._meta && this._meta['isDuplicate'] === 'true';
+    }
+
     public get contentUrl() {
         return this._links['content'].href;
     }

src/Squidex/app/shared/state/asset-uploader.state.ts

@@ -75,7 +75,7 @@ export class AssetUploaderState extends State<Snapshot> {
         const stream = this.assetsService.uploadFile(this.appName, file);
 
         return this.upload(stream, MathHelper.guid(), file, asset  => {
-            if (asset._meta && asset._meta['isDuplicate'] === 'true') {
+            if (asset.isDuplicate) {
                 this.dialogs.notifyError('Asset has already been uploaded.');
             } else if (target) {
                 target.add(asset);