diff --git a/src-ui/src/app/components/document-detail/document-detail.component.ts b/src-ui/src/app/components/document-detail/document-detail.component.ts
index c86976e5f..16d921e8d 100644
--- a/src-ui/src/app/components/document-detail/document-detail.component.ts
+++ b/src-ui/src/app/components/document-detail/document-detail.component.ts
@@ -148,7 +148,7 @@ export class DocumentDetailComponent
     custom_fields: new FormArray([]),
   })
 
-  previewCurrentPage: number
+  previewCurrentPage: number = 1
   previewNumPages: number
   previewZoomSetting: ZoomSetting = ZoomSetting.One
   previewZoomScale: ZoomSetting = ZoomSetting.PageWidth