diff --git a/docs/src/modules/components/JoyThemeBuilder.tsx b/docs/src/modules/components/JoyThemeBuilder.tsx
index a4fc588f4cc30e..c1ab6e0261562a 100644
--- a/docs/src/modules/components/JoyThemeBuilder.tsx
+++ b/docs/src/modules/components/JoyThemeBuilder.tsx
@@ -1494,7 +1494,11 @@ export default function JoyThemeBuilder() {
           <ToggleButtonGroup
             size="sm"
             value={colorMode}
-            onChange={(event, newValue) => setColorMode(newValue as 'light' | 'dark')}
+            onChange={(event, newValue) => {
+              if (newValue) {
+                setColorMode(newValue as 'light' | 'dark');
+              }
+            }}
           >
             <Button value="light">
               <LightMode />