diff --git a/web/app/components/workflow/skill/context.tsx b/web/app/components/workflow/skill/context.tsx
index 6c103d29d8..e286b411d8 100644
--- a/web/app/components/workflow/skill/context.tsx
+++ b/web/app/components/workflow/skill/context.tsx
@@ -1,8 +1,8 @@
 'use client'
 
-import type { SkillEditorStore } from './store'
 import {
   useEffect,
+  useMemo,
   useRef,
 } from 'react'
 import { useStore as useAppStore } from '@/app/components/app/store'
@@ -23,30 +23,24 @@ export type SkillEditorProviderProps = {
 }
 
 export const SkillEditorProvider = ({ children }: SkillEditorProviderProps) => {
-  const storeRef = useRef<SkillEditorStore | undefined>(undefined)
+  // Create store once using useMemo (stable across re-renders)
+  const store = useMemo(() => createSkillEditorStore(), [])
+
   const appDetail = useAppStore(s => s.appDetail)
   const appId = appDetail?.id
   const prevAppIdRef = useRef<string | undefined>(undefined)
 
-  // Create store on first render (pattern recommended by React)
-  if (storeRef.current === null || storeRef.current === undefined)
-    storeRef.current = createSkillEditorStore()
-
   // Reset store when appId changes
   useEffect(() => {
-    if (prevAppIdRef.current !== undefined && prevAppIdRef.current !== appId) {
-      // appId changed, reset the store
-      storeRef.current?.getState().reset()
-    }
+    if (prevAppIdRef.current !== undefined && prevAppIdRef.current !== appId)
+      store.getState().reset()
+
     prevAppIdRef.current = appId
-  }, [appId])
+  }, [appId, store])
 
   return (
-    <SkillEditorContext.Provider value={storeRef.current}>
+    <SkillEditorContext.Provider value={store}>
       {children}
     </SkillEditorContext.Provider>
   )
 }
-
-// Re-export for convenience
-export { SkillEditorContext } from './store'
diff --git a/web/app/components/workflow/skill/editor-tab-item.tsx b/web/app/components/workflow/skill/editor-tab-item.tsx
index aca03d58c4..d39b621cf6 100644
--- a/web/app/components/workflow/skill/editor-tab-item.tsx
+++ b/web/app/components/workflow/skill/editor-tab-item.tsx
@@ -28,7 +28,6 @@ import { getFileIconType } from './utils'
 type EditorTabItemProps = {
   fileId: string
   name: string
-  extension?: string
   isActive: boolean
   isDirty: boolean
   onClick: (fileId: string) => void
@@ -38,7 +37,6 @@ type EditorTabItemProps = {
 const EditorTabItem: FC<EditorTabItemProps> = ({
   fileId,
   name,
-  extension: _extension,
   isActive,
   isDirty,
   onClick,
diff --git a/web/app/components/workflow/skill/editor-tabs.tsx b/web/app/components/workflow/skill/editor-tabs.tsx
index 3fd568af33..093a5c7de8 100644
--- a/web/app/components/workflow/skill/editor-tabs.tsx
+++ b/web/app/components/workflow/skill/editor-tabs.tsx
@@ -36,11 +36,12 @@ const EditorTabs: FC = () => {
   const storeApi = useSkillEditorStoreApi()
 
   // Build node map for quick lookup
+  const treeChildren = treeData?.children
   const nodeMap = useMemo(() => {
-    if (!treeData?.children)
+    if (!treeChildren)
       return new Map<string, AppAssetTreeView>()
-    return buildNodeMap(treeData.children)
-  }, [treeData?.children])
+    return buildNodeMap(treeChildren)
+  }, [treeChildren])
 
   // Handle tab click
   const handleTabClick = (fileId: string) => {
@@ -69,7 +70,6 @@ const EditorTabs: FC = () => {
       {openTabIds.map((fileId) => {
         const node = nodeMap.get(fileId)
         const name = node?.name ?? fileId
-        const extension = node?.extension ?? ''
         const isActive = activeTabId === fileId
         const isDirty = dirtyContents.has(fileId)
 
@@ -78,7 +78,6 @@ const EditorTabs: FC = () => {
             key={fileId}
             fileId={fileId}
             name={name}
-            extension={extension}
             isActive={isActive}
             isDirty={isDirty}
             onClick={handleTabClick}
diff --git a/web/app/components/workflow/skill/file-item.tsx b/web/app/components/workflow/skill/file-item.tsx
deleted file mode 100644
index dedfc02c42..0000000000
--- a/web/app/components/workflow/skill/file-item.tsx
+++ /dev/null
@@ -1,34 +0,0 @@
-import type { FC, ReactNode } from 'react'
-import * as React from 'react'
-import FileTypeIcon from '@/app/components/base/file-uploader/file-type-icon'
-import { cn } from '@/utils/classnames'
-import { getFileIconType } from './utils'
-
-type FileItemProps = {
-  name: string
-  prefix?: ReactNode
-  active?: boolean
-}
-
-const FileItem: FC<FileItemProps> = ({ name, prefix, active = false }) => {
-  const appearanceType = getFileIconType(name)
-
-  return (
-    <div
-      className={cn(
-        'flex h-6 items-center rounded-md pl-2 pr-1.5 text-text-secondary',
-        active && 'bg-state-base-active text-text-primary',
-      )}
-    >
-      {prefix}
-      <div className="flex items-center gap-2 py-0.5">
-        <FileTypeIcon type={appearanceType} size="sm" className={cn(active && 'text-text-primary')} />
-        <span className={cn('system-sm-regular', active && 'font-medium text-text-primary')}>
-          {name}
-        </span>
-      </div>
-    </div>
-  )
-}
-
-export default React.memo(FileItem)
diff --git a/web/app/components/workflow/skill/files.tsx b/web/app/components/workflow/skill/files.tsx
index 714df68ec8..e1a18c1264 100644
--- a/web/app/components/workflow/skill/files.tsx
+++ b/web/app/components/workflow/skill/files.tsx
@@ -84,32 +84,35 @@ const Files: React.FC<FilesProps> = ({ className }) => {
 
   // Auto-reveal when activeTabId changes (sync from tab click to tree)
   useEffect(() => {
-    if (!activeTabId || !treeData?.children)
+    if (!activeTabId || !treeData?.children || !treeRef.current)
       return
 
-    // Get ancestors and expand them
     const ancestors = getAncestorIds(activeTabId, treeData.children)
-    if (ancestors.length > 0) {
-      storeApi.getState().revealFile(activeTabId, ancestors)
-    }
 
-    // Scroll to and select the node
-    if (treeRef.current) {
-      // Small delay to allow tree to update
-      const timeoutId = setTimeout(() => {
-        const node = treeRef.current?.get(activeTabId)
-        if (node) {
-          node.select()
-          // Open all parents programmatically
-          ancestors.forEach((ancestorId) => {
-            const ancestorNode = treeRef.current?.get(ancestorId)
-            if (ancestorNode && !ancestorNode.isOpen)
-              ancestorNode.open()
-          })
-        }
-      }, 0)
-      return () => clearTimeout(timeoutId)
-    }
+    // Update store for state persistence
+    if (ancestors.length > 0)
+      storeApi.getState().revealFile(activeTabId, ancestors)
+
+    // Use Tree API for immediate UI update (initialOpenState only applies on first render)
+    const timeoutId = setTimeout(() => {
+      const tree = treeRef.current
+      if (!tree)
+        return
+
+      // Open all ancestor folders
+      for (const ancestorId of ancestors) {
+        const ancestorNode = tree.get(ancestorId)
+        if (ancestorNode && !ancestorNode.isOpen)
+          ancestorNode.open()
+      }
+
+      // Select the target node
+      const node = tree.get(activeTabId)
+      if (node)
+        node.select()
+    }, 0)
+
+    return () => clearTimeout(timeoutId)
   }, [activeTabId, treeData?.children, storeApi])
 
   // Loading state
diff --git a/web/app/components/workflow/skill/fold-item.tsx b/web/app/components/workflow/skill/fold-item.tsx
deleted file mode 100644
index 62517e95a8..0000000000
--- a/web/app/components/workflow/skill/fold-item.tsx
+++ /dev/null
@@ -1,40 +0,0 @@
-import type { FC, ReactNode } from 'react'
-import { RiFolder6Line, RiFolderOpenLine } from '@remixicon/react'
-import * as React from 'react'
-import { cn } from '@/utils/classnames'
-
-type FoldItemProps = {
-  name: string
-  prefix?: ReactNode
-  active?: boolean
-  open?: boolean
-}
-
-const FoldItem: FC<FoldItemProps> = ({ name, prefix, active = false, open = false }) => {
-  const Icon = open ? RiFolderOpenLine : RiFolder6Line
-
-  return (
-    <div
-      className={cn(
-        'flex h-6 items-center rounded-md pl-2 pr-1.5 text-text-secondary',
-        active && 'bg-state-base-active text-text-primary',
-      )}
-    >
-      {prefix}
-      <div className="flex items-center gap-2 py-0.5">
-        <Icon
-          className={cn(
-            'size-4',
-            open ? 'text-primary-600' : 'text-text-secondary',
-            active && 'text-text-primary',
-          )}
-        />
-        <span className={cn('system-sm-regular', active && 'font-medium text-text-primary')}>
-          {name}
-        </span>
-      </div>
-    </div>
-  )
-}
-
-export default React.memo(FoldItem)
diff --git a/web/app/components/workflow/skill/skill-doc-editor.tsx b/web/app/components/workflow/skill/skill-doc-editor.tsx
index 245a086b61..f2dab8a5d2 100644
--- a/web/app/components/workflow/skill/skill-doc-editor.tsx
+++ b/web/app/components/workflow/skill/skill-doc-editor.tsx
@@ -1,5 +1,6 @@
 'use client'
 
+import type { OnMount } from '@monaco-editor/react'
 import type { FC } from 'react'
 import type { AppAssetTreeView } from './type'
 import Editor, { loader } from '@monaco-editor/react'
@@ -39,7 +40,7 @@ const SkillDocEditor: FC = () => {
   const { t } = useTranslation('workflow')
   const { theme: appTheme } = useTheme()
   const [isMounted, setIsMounted] = useState(false)
-  const editorRef = useRef<any>(null)
+  const editorRef = useRef<Parameters<OnMount>[0] | null>(null)
 
   // Get appId from app store
   const appDetail = useAppStore(s => s.appDetail)
@@ -54,11 +55,12 @@ const SkillDocEditor: FC = () => {
   const { data: treeData } = useGetAppAssetTree(appId)
 
   // Build node map for quick lookup
+  const treeChildren = treeData?.children
   const nodeMap = useMemo(() => {
-    if (!treeData?.children)
+    if (!treeChildren)
       return new Map<string, AppAssetTreeView>()
-    return buildNodeMap(treeData.children)
-  }, [treeData?.children])
+    return buildNodeMap(treeChildren)
+  }, [treeChildren])
 
   // Get current file node
   const currentFileNode = activeTabId ? nodeMap.get(activeTabId) : undefined
@@ -138,7 +140,7 @@ const SkillDocEditor: FC = () => {
   }, [handleSave])
 
   // Handle editor mount
-  const handleEditorDidMount = useCallback((editor: any, monaco: any) => {
+  const handleEditorDidMount: OnMount = useCallback((editor, monaco) => {
     editorRef.current = editor
     monaco.editor.setTheme(appTheme === Theme.light ? 'light' : 'vs-dark')
     setIsMounted(true)
diff --git a/web/app/components/workflow/skill/type.ts b/web/app/components/workflow/skill/type.ts
index cd52d44818..25e0ff5eab 100644
--- a/web/app/components/workflow/skill/type.ts
+++ b/web/app/components/workflow/skill/type.ts
@@ -96,18 +96,6 @@ export function getAncestorIds(nodeId: string, nodes: AppAssetTreeView[]): strin
   return ancestors
 }
 
-/**
- * Get file extension from file name
- * @param name - File name (e.g., 'file.txt')
- * @returns Extension without dot (e.g., 'txt') or empty string
- */
-export function getExtension(name: string): string {
-  const lastDot = name.lastIndexOf('.')
-  if (lastDot === -1 || lastDot === 0)
-    return ''
-  return name.slice(lastDot + 1).toLowerCase()
-}
-
 /**
  * Convert expanded folder IDs set to react-arborist opens object
  * @param expandedIds - Set of expanded folder IDs
@@ -120,17 +108,3 @@ export function toOpensObject(expandedIds: Set<string>): Record<string, boolean>
   })
   return opens
 }
-
-/**
- * Convert react-arborist opens object to Set
- * @param opens - Opens object from react-arborist
- * @returns Set of expanded folder IDs
- */
-export function fromOpensObject(opens: Record<string, boolean>): Set<string> {
-  const set = new Set<string>()
-  Object.entries(opens).forEach(([id, isOpen]) => {
-    if (isOpen)
-      set.add(id)
-  })
-  return set
-}