diff --git a/src-ui/src/app/components/common/confirm-dialog/merge-as-versions-confirm-dialog/merge-as-versions-confirm-dialog.component.ts b/src-ui/src/app/components/common/confirm-dialog/merge-as-versions-confirm-dialog/merge-as-versions-confirm-dialog.component.ts
index 5fb69fc92..a05e3ab1b 100644
--- a/src-ui/src/app/components/common/confirm-dialog/merge-as-versions-confirm-dialog/merge-as-versions-confirm-dialog.component.ts
+++ b/src-ui/src/app/components/common/confirm-dialog/merge-as-versions-confirm-dialog/merge-as-versions-confirm-dialog.component.ts
@@ -64,7 +64,7 @@ export class MergeAsVersionsConfirmDialogComponent
     )
   }
 
-  getDocument(documentID: number): Document {
+  getDocument(documentID: number): Document | undefined {
     return this.documents().find((document) => document.id === documentID)
   }
 }