diff --git a/autohide.js b/autohide.js
index d47d6a7..fea3582 100644
--- a/autohide.js
+++ b/autohide.js
@@ -251,7 +251,9 @@ export let AutoHide = class {
       (w) =>
         workspace == w.get_workspace().index() && w.showing_on_its_workspace()
     );
-    windows = windows.filter((w) => w.get_window_type() in handledWindowTypes);
+    windows = windows.filter((w) =>
+      handledWindowTypes.includes(w.get_window_type())
+    );
 
     let isOverlapped = false;
     let dockRect = this.dock.struts.get_transformed_position();