Hide preview after all documents removed

src-ui/src/app/components/split-merge/split-merge.component.html

@@ -104,7 +104,7 @@
       <div *ngIf="loading" class="spinner-border" role="status">
         <span class="sr-only" i18n>Loading...</span>
       </div>
-      <pdf-viewer [src]="previewUrls[0]" [original-size]="false" [show-borders]="true" [show-all]="true" [render-text-mode]="2" (after-load-complete)="pdfPreviewLoaded($event)"></pdf-viewer>
+      <pdf-viewer *ngIf="previewUrls.length > 0" [src]="previewUrls[0]" [original-size]="false" [show-borders]="true" [show-all]="true" [render-text-mode]="2" (after-load-complete)="pdfPreviewLoaded($event)"></pdf-viewer>
     </div>
   </div>
 </div>

src-ui/src/app/components/split-merge/split-merge.component.ts

@@ -40,9 +40,11 @@ export class SplitMergeComponent implements OnInit, OnDestroy {
     ).subscribe(() => {
       if (this.splitMergeService.hasDocuments()) {
         this.save(true)
+      } else {
+        this.previewUrls = []
       }
     })
-    if (this.splitMergeService.hasDocuments()) this.previewDebounce$.next()
+    this.previewDebounce$.next()
   }
 
   ngOnDestroy() {