diff --git a/web/src/types/timeline.ts b/web/src/types/timeline.ts
index 45a0821ed..aa6762111 100644
--- a/web/src/types/timeline.ts
+++ b/web/src/types/timeline.ts
@@ -29,7 +29,7 @@ export type ObjectLifecycleSequence = {
 
 export type TimeRange = { before: number; after: number };
 
-export type TimelineType = "timeline" | "events";
+export type TimelineType = "timeline" | "events" | "activity";
 
 export type TimelineScrubMode = "auto" | "drag" | "hover" | "compat";