diff --git a/.gitignore b/.gitignore
index 58ea7ad..0c58568 100644
--- a/.gitignore
+++ b/.gitignore
@@ -7,6 +7,7 @@
 
 # dependencies
 /ui/node_modules
+/ui/package-lock.json
 
 # profiling files
 chrome-profiler-events*.json
diff --git a/ui/package.json b/ui/package.json
index 3c87629..604f0ad 100644
--- a/ui/package.json
+++ b/ui/package.json
@@ -38,6 +38,7 @@
     "@fortawesome/free-solid-svg-icons": "^7.1.0",
     "@ng-bootstrap/ng-bootstrap": "^20.0.0",
     "@ng-select/ng-select": "^21.1.0",
+    "@popperjs/core": "^2.11.8",
     "bootstrap": "^5.3.6",
     "ngx-cookie-service": "^21.1.0",
     "ngx-socket-io": "~4.9.3",
@@ -59,4 +60,4 @@
     "typescript-eslint": "8.47.0",
     "vitest": "^4.0.8"
   }
-}
\ No newline at end of file
+}
diff --git a/ui/src/app/services/downloads.service.ts b/ui/src/app/services/downloads.service.ts
index a63f637..7285f39 100644
--- a/ui/src/app/services/downloads.service.ts
+++ b/ui/src/app/services/downloads.service.ts
@@ -118,12 +118,15 @@ export class DownloadsService {
   }
 
   public delById(where: State, ids: string[]) {
-    ids.forEach(id => {
-      const obj = this[where].get(id)
-      if (obj) {
-        obj.deleting = true
+    const map = this[where];
+    if (map) {
+      for (const id of ids) {
+        const obj = map.get(id);
+        if (obj) {
+          obj.deleting = true;
+        }
       }
-  });
+    }
     return this.http.post('delete', {where: where, ids: ids});
   }