js/src/features/particles/stream-view.tsx

@@ -79,6 +79,10 @@ function playbackReducer(
       if (action.particleCount === 0) {
         return { currentIndex: 0, status: "idle", paused: state.paused };
       }
+      if (state.status === "ended" && state.currentIndex < action.particleCount - 1) {
+        // New particle appended — resume and advance to it
+        return { ...state, currentIndex: state.currentIndex + 1, status: "playing", paused: false };
+      }
       if (state.currentIndex >= action.particleCount) {
         return { ...state, currentIndex: action.particleCount - 1 };
       }