diff --git a/packages/studio/src/hooks/timelineEditingHelpers.ts b/packages/studio/src/hooks/timelineEditingHelpers.ts
index 4483610e0..cbe4fcf6d 100644
--- a/packages/studio/src/hooks/timelineEditingHelpers.ts
+++ b/packages/studio/src/hooks/timelineEditingHelpers.ts
@@ -190,7 +190,7 @@ export function patchIframeDomTiming(
   }
 }
 
-export function postRootDurationToPreview(
+function postRootDurationToPreview(
   iframe: HTMLIFrameElement | null,
   durationSeconds: number,
 ): void {
diff --git a/packages/studio/src/player/components/Timeline.tsx b/packages/studio/src/player/components/Timeline.tsx
index 88b6a7863..5b26dae89 100644
--- a/packages/studio/src/player/components/Timeline.tsx
+++ b/packages/studio/src/player/components/Timeline.tsx
@@ -230,9 +230,7 @@ export const Timeline = memo(function Timeline({
     setRangeSelectionRef,
   });
 
-  // basisDuration drives the zoom (committed, no live preview); effectiveDuration
-  // adds the active drag/resize preview so the ruler/width follow a past-end drag.
-  // See timelineLayout for why the split prevents jump-during-extend.
+  // basis drives the zoom (committed); effective adds the live preview (see timelineLayout).
   const basisDuration = useMemo(
     () =>
       computeTimelineBasisDuration(