diff --git a/packages/app/src/agent-stream/strategy-web.tsx b/packages/app/src/agent-stream/strategy-web.tsx
index 15b552039..60a0ad961 100644
--- a/packages/app/src/agent-stream/strategy-web.tsx
+++ b/packages/app/src/agent-stream/strategy-web.tsx
@@ -152,6 +152,7 @@ function WebStreamViewport(props: StreamRenderInput & { isMobileBreakpoint: bool
 
   const rowVirtualizer = useVirtualizer({
     count: segments.historyVirtualized.length,
+    enabled: shouldUseVirtualizer,
     getScrollElement: () => scrollContainerRef.current,
     getItemKey: (index: number) => segments.historyVirtualized[index]?.id ?? index,
     estimateSize: (index: number) => {