diff --git a/scripts/build-webviews.js b/scripts/build-webviews.js
index 37246d5..755f7b1 100644
--- a/scripts/build-webviews.js
+++ b/scripts/build-webviews.js
@@ -21,6 +21,7 @@ const buildOptions = {
     format: 'iife',
     target: 'es2020',
     sourcemap: false,
+    minify: !watch,
     legalComments: 'none',
     logLevel: 'info'
 };
diff --git a/src/notifications/notificationService.ts b/src/notifications/notificationService.ts
index c2e2034..9519ef8 100644
--- a/src/notifications/notificationService.ts
+++ b/src/notifications/notificationService.ts
@@ -86,6 +86,7 @@ export class NotificationService implements vscode.Disposable {
     private async pollOnce(): Promise<void> {
         if (this._disposed || this._polling) { return; }
         if (!this._client.isConnected) { return; }
+        if (!vscode.window.state.focused) { return; }
         this._polling = true;
         try {
             let scopes;
diff --git a/src/providers/pipelinesProvider.ts b/src/providers/pipelinesProvider.ts
index 3a439f0..8dc85ea 100644
--- a/src/providers/pipelinesProvider.ts
+++ b/src/providers/pipelinesProvider.ts
@@ -181,12 +181,35 @@ type PipelinesTreeNode =
     | PipelineStepLogNode
     | vscode.TreeItem;
 
+class TimelineCache {
+    private readonly _map = new Map<string, PipelineTimelineRecord[]>();
+    constructor(private readonly _maxSize: number) {}
+
+    get(key: string): PipelineTimelineRecord[] | undefined {
+        return this._map.get(key);
+    }
+
+    set(key: string, value: PipelineTimelineRecord[]): void {
+        if (this._map.size >= this._maxSize && !this._map.has(key)) {
+            const oldest = this._map.keys().next().value;
+            if (oldest !== undefined) {
+                this._map.delete(oldest);
+            }
+        }
+        this._map.set(key, value);
+    }
+
+    clear(): void {
+        this._map.clear();
+    }
+}
+
 export class PipelinesProvider implements vscode.TreeDataProvider<PipelinesTreeNode> {
     private _onDidChangeTreeData = new vscode.EventEmitter<PipelinesTreeNode | undefined | null | void>();
     readonly onDidChangeTreeData = this._onDidChangeTreeData.event;
 
     private _loading = false;
-    private readonly timelineCache = new Map<string, PipelineTimelineRecord[]>();
+    private readonly timelineCache = new TimelineCache(200);
 
     constructor(
         private readonly client: AdoClient,