diff --git a/package-lock.json b/package-lock.json
index 37c11f8..7012e7f 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -18,9 +18,6 @@
           "version": "6.5.3",
           "resolved": "http://10.81.13.229:8081/repository/npm-all/rxjs/-/rxjs-6.5.3.tgz",
           "integrity": "sha512-wuYsAYYFdWTAnAaPoKGNhfpWwKZbJW+HgAJ+mImp+Epl7BG8oNWBCTyRM8gba9k4lk8BgWdoYm21Mo/RYhhbgA==",
-          "dev": true,
-          "requires": {
-            "tslib": "^1.9.0"
           }
         }
       }
@@ -125,10 +122,8 @@
             "source-map": {
               "version": "0.5.7",
               "resolved": "http://10.81.13.229:8081/repository/npm-all/source-map/-/source-map-0.5.7.tgz",
-              "integrity": "sha1-igOdLRAh0i0eoUyA2OpGi6LvP8w=",
-              "dev": true
+              "integrity": "sha1-igOdLRAh0i0eoUyA2OpGi6LvP8w="
             }
-          }
         },
         "babel-loader": {
           "version": "8.0.6",
diff --git a/projects/ui-group/src/lib/components/expansion.component.ts b/projects/ui-group/src/lib/components/expansion.component.ts
index c519c10..88663f6 100644
--- a/projects/ui-group/src/lib/components/expansion.component.ts
+++ b/projects/ui-group/src/lib/components/expansion.component.ts
@@ -228,9 +228,8 @@ export class ExpansionComponent implements OnInit, OnDestroy {
 
   NodeType = NodeType;
 
-  private nodeMap: Map<NodeType, GroupNode[]> = new Map();
-  // tslint:disable-next-line: variable-name
   private _ngOnDestroySubject: Subject<void>;
+  private nodeMap: Map<NodeType, GroupNode[]>;
 
   constructor(private changeDetectorRef: ChangeDetectorRef) {
     this.treeControl = new FlatTreeControl<FlatNode>(
@@ -275,8 +274,11 @@ export class ExpansionComponent implements OnInit, OnDestroy {
       this._ngOnDestroySubject.next();
       this._ngOnDestroySubject.complete();
     }
+
+    this.dataSource.cdkVirtualScrollViewport = this.cvsvList;
   }
 
+
   onClickHeaderMenu(event: MouseEvent, node: FlatNode) {}
 
   isCheckedGroup(node: FlatNode): boolean {