fix(web): contain pipeline debug scrolling

web/src/app/home/pipelines/components/debug-dialog/DebugDialog.tsx

@@ -144,7 +144,7 @@ export default function DebugDialog({
     new Set(),
   );
   const [streamOutput, setStreamOutput] = useState(true);
-  const messagesEndRef = useRef<HTMLDivElement>(null);
+  const scrollAreaRef = useRef<HTMLDivElement>(null);
   const inputRef = useRef<HTMLInputElement>(null);
   const popoverRef = useRef<HTMLDivElement>(null);
   const fileInputRef = useRef<HTMLInputElement>(null);
@@ -152,17 +152,14 @@ export default function DebugDialog({
   const isInitializingRef = useRef<boolean>(false);
 
   const scrollToBottom = useCallback(() => {
-    // Use setTimeout to ensure scroll happens after DOM update
     setTimeout(() => {
-      const scrollArea = document.querySelector('.scroll-area') as HTMLElement;
-      if (scrollArea) {
-        scrollArea.scrollTo({
-          top: scrollArea.scrollHeight,
-          behavior: 'smooth',
-        });
-      }
-      // Also ensure messagesEndRef scrolls into view
-      messagesEndRef.current?.scrollIntoView({ behavior: 'smooth' });
+      const viewport = scrollAreaRef.current?.querySelector<HTMLElement>(
+        '[data-slot="scroll-area-viewport"]',
+      );
+      viewport?.scrollTo({
+        top: viewport.scrollHeight,
+        behavior: 'smooth',
+      });
     }, 0);
   }, []);
 
@@ -843,6 +840,7 @@ export default function DebugDialog({
 
       <div className="flex-1 flex flex-col w-[10rem] h-full min-h-0">
         <ScrollArea
+          ref={scrollAreaRef}
           className={cn(
             'flex-1 overflow-y-auto min-h-0 scroll-area',
             compact ? 'p-3' : 'p-6',
@@ -934,7 +932,6 @@ export default function DebugDialog({
                 </div>
               ))
             )}
-            <div ref={messagesEndRef} />
           </div>
         </ScrollArea>
 

web/tests/e2e/processor-detail-workbench.spec.ts

@@ -27,6 +27,12 @@ test.describe('processor detail workbench', () => {
     expect(debugBox!.x).toBeLessThan(configBox!.x);
     expect(configBox!.width).toBeGreaterThan(debugBox!.width);
 
+    const appShell = page.locator('[class*="group/sidebar-wrapper"]');
+    await expect
+      .poll(() => appShell.evaluate((element) => element.scrollTop))
+      .toBe(0);
+    expect(debugBox!.y).toBeGreaterThanOrEqual(0);
+
     const flow = configPanel.locator('ol');
     await expect(flow.getByRole('button').nth(0)).toContainText(
       'Bindable Event Range',
@@ -63,6 +69,12 @@ test.describe('processor detail workbench', () => {
     expect(debugBox!.x).toBeLessThan(configBox!.x);
     expect(configBox!.width).toBeGreaterThan(debugBox!.width);
 
+    const appShell = page.locator('[class*="group/sidebar-wrapper"]');
+    await expect
+      .poll(() => appShell.evaluate((element) => element.scrollTop))
+      .toBe(0);
+    expect(debugBox!.y).toBeGreaterThanOrEqual(0);
+
     const flow = configPanel.locator('ol');
     await expect(flow.getByRole('button').nth(0)).toContainText(
       'Trigger Conditions',

web/tests/unit/processor-detail-workbench.test.mjs

@@ -22,6 +22,9 @@ test('agent and pipeline details share the split processor workbench', () => {
   const websocketClient = readSource(
     'src/app/infra/websocket/WebSocketClient.ts',
   );
+  const pipelineDebug = readSource(
+    'src/app/home/pipelines/components/debug-dialog/DebugDialog.tsx',
+  );
 
   assert.match(
     workbench,
@@ -42,6 +45,8 @@ test('agent and pipeline details share the split processor workbench', () => {
     websocketClient,
     /data\.type === 'connected'[\s\S]*this\.reconnectAttempts = 0/,
   );
+  assert.match(pipelineDebug, /data-slot="scroll-area-viewport"/);
+  assert.doesNotMatch(pipelineDebug, /scrollIntoView/);
 });
 
 test('processor forms expose their primary orchestration flow horizontally', () => {