1 files changed, 11 insertions, 4 deletions
diff --git a/src/client/views/collections/CollectionBaseView.tsx b/src/client/views/collections/CollectionBaseView.tsx
index b5eaab349..4fda38a26 100644
--- a/src/client/views/collections/CollectionBaseView.tsx
+++ b/src/client/views/collections/CollectionBaseView.tsx
@@ -1,4 +1,4 @@
-import { action } from 'mobx';
+import { action, computed } from 'mobx';
 import { observer } from 'mobx-react';
 import * as React from 'react';
 import { Document } from '../../../fields/Document';
@@ -61,13 +61,16 @@ export class CollectionBaseView extends React.Component<CollectionViewProps> {
     }
 
     createsCycle(documentToAdd: Document, containerDocument: Document): boolean {
-        let data = documentToAdd.GetList<Document>(KeyStore.Data, []);
-        for (const doc of data) {
+        if (!(documentToAdd instanceof Document)) {
+            return false;
+        }
+        let data = documentToAdd.GetList(KeyStore.Data, [] as Document[]);
+        for (const doc of data.filter(d => d instanceof Document)) {
             if (this.createsCycle(doc, containerDocument)) {
                 return true;
             }
         }
-        let annots = documentToAdd.GetList<Document>(KeyStore.Annotations, []);
+        let annots = documentToAdd.GetList(KeyStore.Annotations, [] as Document[]);
         for (const annot of annots) {
             if (this.createsCycle(annot, containerDocument)) {
                 return true;
@@ -80,12 +83,16 @@ export class CollectionBaseView extends React.Component<CollectionViewProps> {
         }
         return false;
     }
+    @computed get isAnnotationOverlay() { return this.props.fieldKey && this.props.fieldKey.Id === KeyStore.Annotations.Id; } // bcz: ? Why do we need to compare Id's?
 
     @action.bound
     addDocument(doc: Document, allowDuplicates: boolean = false): boolean {
         let props = this.props;
         var curPage = props.Document.GetNumber(KeyStore.CurPage, -1);
         doc.SetOnPrototype(KeyStore.Page, new NumberField(curPage));
+        if (this.isAnnotationOverlay) {
+            doc.SetNumber(KeyStore.Zoom, this.props.Document.GetNumber(KeyStore.Scale, 1));
+        }
         if (curPage >= 0) {
             doc.SetOnPrototype(KeyStore.AnnotationOn, props.Document);
         }