diff --git a/src/pages/XRSession.tsx b/src/pages/XRSession.tsx
index 7b18f37..d2df4a7 100644
--- a/src/pages/XRSession.tsx
+++ b/src/pages/XRSession.tsx
@@ -580,6 +580,11 @@ const XRSession = () => {
           allowScale={allowScale}
           onToggleAllowScale={() => setAllowScale(!allowScale)}
         />
+
+        {/* DEVKIT: floating diagnostic panel + SimXR toggle */}
+        {devkit && (
+          <DevPanel simXR={simXR} onToggleSimXR={() => setSimXR((v) => !v)} />
+        )}
       </div>
     </div>
   );