Fix agent manager diff viewer collapse and scroll reset (#6406)

* Fix file view collapse regressions

* Fix agent manager diff viewer collapse and scroll reset bugs

Reset openInit flag when switching sessions via a new sessionKey prop so
diff files auto-expand for each session instead of staying collapsed.

Stabilize diff data references during 2.5s polling to prevent <For> from
tearing down and rebuilding <Diff> components, which destroyed scroll
position. Guard setOpen in the auto-open effect to skip updates when the
file list is unchanged.

* remove package.json

packages/kilo-vscode/webview-ui/agent-manager/AgentManagerApp.tsx

@@ -934,7 +934,24 @@ const AgentManagerContent: Component = () => {
 
       if (msg.type === "agentManager.worktreeDiff") {
         const ev = msg as AgentManagerWorktreeDiffMessage
-        setDiffDatas((prev) => ({ ...prev, [ev.sessionId]: ev.diffs }))
+        setDiffDatas((prev) => {
+          const existing = prev[ev.sessionId]
+          // Reuse previous array reference when content is unchanged to prevent
+          // <For> from tearing down / rebuilding <Diff> components (which resets scroll)
+          if (existing && existing.length === ev.diffs.length) {
+            const same = existing.every((old, i) => {
+              const next = ev.diffs[i]!
+              return (
+                old.file === next.file &&
+                old.before === next.before &&
+                old.after === next.after &&
+                old.status === next.status
+              )
+            })
+            if (same) return prev
+          }
+          return { ...prev, [ev.sessionId]: ev.diffs }
+        })
       }
 
       if (msg.type === "agentManager.worktreeDiffLoading") {
@@ -2059,6 +2076,7 @@ const AgentManagerContent: Component = () => {
                   <DiffPanel
                     diffs={diffDatas()[selection() === LOCAL ? LOCAL : (session.currentSessionID() ?? "")] ?? []}
                     loading={diffLoading()}
+                    sessionKey={selection() === LOCAL ? LOCAL : (session.currentSessionID() ?? "")}
                     diffStyle={reviewDiffStyle()}
                     onDiffStyleChange={setSharedDiffStyle}
                     comments={reviewComments()}
@@ -2080,6 +2098,7 @@ const AgentManagerContent: Component = () => {
               <FullScreenDiffView
                 diffs={reviewDiffs()}
                 loading={diffLoading()}
+                sessionKey={selection() === LOCAL ? LOCAL : (session.currentSessionID() ?? "")}
                 comments={reviewComments()}
                 onCommentsChange={setReviewCommentsForSelection}
                 onSendAll={closeReviewTab}

packages/kilo-vscode/webview-ui/agent-manager/DiffPanel.tsx

@@ -27,6 +27,7 @@ import { buildReviewAnnotation, type AnnotationLabels, type AnnotationMeta } fro
 interface DiffPanelProps {
   diffs: WorktreeFileDiff[]
   loading: boolean
+  sessionKey?: string
   diffStyle?: "unified" | "split"
   onDiffStyleChange?: (style: "unified" | "split") => void
   comments: ReviewComment[]
@@ -111,13 +112,31 @@ export const DiffPanel: Component<DiffPanelProps> = (props) => {
     focusRoot()
   }
 
+  // Reset auto-open state when switching sessions so diffs expand for the new session
+  createEffect(
+    on(
+      () => props.sessionKey,
+      () => {
+        setOpenInit(false)
+      },
+      { defer: true },
+    ),
+  )
+
   // Auto-open files when diffs arrive
   createEffect(
     on(
       () => props.diffs,
       (diffs) => {
         const files = diffs.map((d) => d.file)
-        setOpen((prev) => prev.filter((file) => files.includes(file)))
+        const fileSet = new Set(files)
+        // Only update open state when the file list actually changed to avoid
+        // unnecessary re-renders that reset scroll position during polling
+        setOpen((prev) => {
+          const filtered = prev.filter((file) => fileSet.has(file))
+          if (filtered.length === prev.length && prev.every((f) => fileSet.has(f))) return prev
+          return filtered
+        })
         if (openInit()) return
         if (diffs.length === 0) return
         if (diffs.length <= 15) setOpen(files)

packages/kilo-vscode/webview-ui/agent-manager/FullScreenDiffView.tsx

@@ -29,6 +29,7 @@ type DiffStyle = "unified" | "split"
 interface FullScreenDiffViewProps {
   diffs: WorktreeFileDiff[]
   loading: boolean
+  sessionKey?: string
   comments: ReviewComment[]
   onCommentsChange: (comments: ReviewComment[]) => void
   onSendAll?: () => void
@@ -104,13 +105,31 @@ export const FullScreenDiffView: Component<FullScreenDiffViewProps> = (props) =>
     focusRoot()
   }
 
+  // Reset auto-open state when switching sessions so diffs expand for the new session
+  createEffect(
+    on(
+      () => props.sessionKey,
+      () => {
+        setOpenInit(false)
+      },
+      { defer: true },
+    ),
+  )
+
   // Auto-open files when diffs arrive
   createEffect(
     on(
       () => props.diffs,
       (diffs) => {
         const files = diffs.map((d) => d.file)
-        setOpen((prev) => prev.filter((file) => files.includes(file)))
+        const fileSet = new Set(files)
+        // Only update open state when the file list actually changed to avoid
+        // unnecessary re-renders that reset scroll position during polling
+        setOpen((prev) => {
+          const filtered = prev.filter((file) => fileSet.has(file))
+          if (filtered.length === prev.length && prev.every((f) => fileSet.has(f))) return prev
+          return filtered
+        })
         if (diffs.length === 0) {
           setActiveFile(null)
           return