diff --git a/filemanager/js/app.ts b/filemanager/js/app.ts
index da470dc064..63f1bdd35b 100644
--- a/filemanager/js/app.ts
+++ b/filemanager/js/app.ts
@@ -13,4 +13,7 @@ import {filemanagerAPP} from "./filemanager";
 /**
  * This is the app.ts endpoint, code is in ./filemanager.ts to ensure proper loading/cache-invalidation for Collabora extending filemanagerAPP!
  */
-app.classes.filemanager = filemanagerAPP;
+if(typeof app.classes.filemanager === "undefined")
+{
+	app.classes.filemanager = filemanagerAPP;
+}
diff --git a/filemanager/js/filemanager.ts b/filemanager/js/filemanager.ts
index 2f9ddf9235..40890b84ab 100644
--- a/filemanager/js/filemanager.ts
+++ b/filemanager/js/filemanager.ts
@@ -1444,4 +1444,3 @@ export class filemanagerAPP extends EgwApp
 		}
 	}
 }
-app.classes.filemanager = filemanagerAPP;