diff --git a/rare/components/tabs/settings/widgets/env_vars_model.py b/rare/components/tabs/settings/widgets/env_vars_model.py
index fdf03b38..29ca61b5 100644
--- a/rare/components/tabs/settings/widgets/env_vars_model.py
+++ b/rare/components/tabs/settings/widgets/env_vars_model.py
@@ -28,14 +28,15 @@ class EnvVarsTableModel(QAbstractTableModel):
         self.__validator = re.compile(r"(^[A-Za-z_][A-Za-z0-9_]*)")
         self.__data_map: ChainMap = ChainMap()
 
-        self.__readonly = [
+        self.__readonly = {
             "DXVK_HUD",
+            "MANGOHUD",
             "MANGOHUD_CONFIG",
-        ]
+        }
         if platform.system() != "Windows":
-            self.__readonly.extend(get_wine_environment().keys())
+            self.__readonly.update(get_wine_environment().keys())
         if platform.system() in {"Linux", "FreeBSD"}:
-            self.__readonly.extend(get_steam_environment().keys())
+            self.__readonly.update(get_steam_environment().keys())
 
         self.__default: str = "default"
         self.__appname: str = None