diff --git a/system/ui/lib/application.py b/system/ui/lib/application.py
index 4d7ba6d24e..37da413806 100644
--- a/system/ui/lib/application.py
+++ b/system/ui/lib/application.py
@@ -192,7 +192,7 @@ class GuiApplication:
 
     # Create a character set from our keyboard layouts
     from openpilot.system.ui.widgets.keyboard import KEYBOARD_LAYOUTS
-    all_chars = ""
+    all_chars = set()
     for layout in KEYBOARD_LAYOUTS.values():
       all_chars.update(key for row in layout for key in row)
     all_chars = "".join(all_chars)