diff --git a/extensions/git/src/timelineProvider.ts b/extensions/git/src/timelineProvider.ts
index f2701c4be01..d6e2be8613b 100644
--- a/extensions/git/src/timelineProvider.ts
+++ b/extensions/git/src/timelineProvider.ts
@@ -227,6 +227,6 @@ export class GitTimelineProvider implements TimelineProvider {
 
 	@debounce(500)
 	private fireChanged() {
-		this._onDidChange.fire({ reset: true });
+		this._onDidChange.fire(undefined);
 	}
 }
diff --git a/src/vs/vscode.proposed.d.ts b/src/vs/vscode.proposed.d.ts
index 12dce38ecc6..713811c91b3 100644
--- a/src/vs/vscode.proposed.d.ts
+++ b/src/vs/vscode.proposed.d.ts
@@ -1890,9 +1890,8 @@ declare module 'vscode' {
 	export interface TimelineChangeEvent {
 		/**
 		 * The [uri](#Uri) of the resource for which the timeline changed.
-		 * If the [uri](#Uri) is `undefined` that signals that the timeline source for all resources changed.
 		 */
-		uri?: Uri;
+		uri: Uri;
 
 		/**
 		 * A flag which indicates whether the entire timeline should be reset.
@@ -1933,7 +1932,7 @@ declare module 'vscode' {
 		 * An optional event to signal that the timeline for a source has changed.
 		 * To signal that the timeline for all resources (uris) has changed, do not pass any argument or pass `undefined`.
 		 */
-		onDidChange?: Event<TimelineChangeEvent>;
+		onDidChange?: Event<TimelineChangeEvent | undefined>;
 
 		/**
 		 * An identifier of the source of the timeline items. This can be used to filter sources.
diff --git a/src/vs/workbench/api/common/extHost.protocol.ts b/src/vs/workbench/api/common/extHost.protocol.ts
index 1aa6d171ff2..55981239258 100644
--- a/src/vs/workbench/api/common/extHost.protocol.ts
+++ b/src/vs/workbench/api/common/extHost.protocol.ts
@@ -885,7 +885,7 @@ export interface MainThreadTunnelServiceShape extends IDisposable {
 export interface MainThreadTimelineShape extends IDisposable {
 	$registerTimelineProvider(provider: TimelineProviderDescriptor): void;
 	$unregisterTimelineProvider(source: string): void;
-	$emitTimelineChangeEvent(e: TimelineChangeEvent): void;
+	$emitTimelineChangeEvent(e: TimelineChangeEvent | undefined): void;
 }
 
 // -- extension host
diff --git a/src/vs/workbench/api/common/extHostTimeline.ts b/src/vs/workbench/api/common/extHostTimeline.ts
index 4df94da98d5..c15a9e73617 100644
--- a/src/vs/workbench/api/common/extHostTimeline.ts
+++ b/src/vs/workbench/api/common/extHostTimeline.ts
@@ -60,7 +60,7 @@ export class ExtHostTimeline implements IExtHostTimeline {
 
 		let disposable: IDisposable | undefined;
 		if (provider.onDidChange) {
-			disposable = provider.onDidChange(e => this._proxy.$emitTimelineChangeEvent({ ...e, id: provider.id }), this);
+			disposable = provider.onDidChange(e => this._proxy.$emitTimelineChangeEvent({ uri: undefined, reset: true, ...e, id: provider.id }), this);
 		}
 
 		const itemsBySourceAndUriMap = this._itemsBySourceAndUriMap;
diff --git a/src/vs/workbench/contrib/timeline/browser/timelinePane.ts b/src/vs/workbench/contrib/timeline/browser/timelinePane.ts
index 5c4307dfbb1..ae8eca65ff6 100644
--- a/src/vs/workbench/contrib/timeline/browser/timelinePane.ts
+++ b/src/vs/workbench/contrib/timeline/browser/timelinePane.ts
@@ -359,9 +359,9 @@ export class TimelinePane extends ViewPane {
 			}
 
 			if (this.isBodyVisible()) {
-				this.updateTimeline(timeline, e.reset ?? false);
+				this.updateTimeline(timeline, e.reset);
 			} else {
-				timeline.invalidate(e.reset ?? false);
+				timeline.invalidate(e.reset);
 			}
 		}
 	}
diff --git a/src/vs/workbench/contrib/timeline/common/timeline.ts b/src/vs/workbench/contrib/timeline/common/timeline.ts
index 84877649f50..c84c77e41f9 100644
--- a/src/vs/workbench/contrib/timeline/common/timeline.ts
+++ b/src/vs/workbench/contrib/timeline/common/timeline.ts
@@ -38,8 +38,8 @@ export interface TimelineItem {
 
 export interface TimelineChangeEvent {
 	id: string;
-	uri?: URI;
-	reset?: boolean
+	uri: URI | undefined;
+	reset: boolean
 }
 
 export interface TimelineOptions {