diff --git a/Changelog.md b/Changelog.md
index d0165c2a0..d01e4a0c2 100644
--- a/Changelog.md
+++ b/Changelog.md
@@ -7,6 +7,7 @@
 - macOS 非预期 Tproxy 端口设置
 - 流量图缩放异常
 - PAC 自动代理脚本内容无法动态调整
+- Monaco 编辑器的行数上限
 
 <details>
 <summary><strong> ✨ 新增功能 </strong></summary>
diff --git a/src/components/base/base-loading-overlay.tsx b/src/components/base/base-loading-overlay.tsx
index 98727dcb1..a115da25c 100644
--- a/src/components/base/base-loading-overlay.tsx
+++ b/src/components/base/base-loading-overlay.tsx
@@ -21,7 +21,11 @@ export const BaseLoadingOverlay: React.FC<BaseLoadingOverlayProps> = ({
         display: "flex",
         justifyContent: "center",
         alignItems: "center",
-        backgroundColor: "rgba(255, 255, 255, 0.7)",
+        // Respect current theme; avoid bright flash in dark mode
+        backgroundColor: (theme) =>
+          theme.palette.mode === "dark"
+            ? "rgba(0, 0, 0, 0.5)"
+            : "rgba(255, 255, 255, 0.7)",
         zIndex: 1000,
       }}
     >
diff --git a/src/components/profile/editor-viewer.tsx b/src/components/profile/editor-viewer.tsx
index 64f2e1675..d5d16495b 100644
--- a/src/components/profile/editor-viewer.tsx
+++ b/src/components/profile/editor-viewer.tsx
@@ -21,10 +21,11 @@ import metaSchema from "meta-json-schema/schemas/meta-json-schema.json";
 import * as monaco from "monaco-editor";
 import { configureMonacoYaml } from "monaco-yaml";
 import { nanoid } from "nanoid";
-import { ReactNode, useEffect, useMemo, useRef, useState } from "react";
+import { ReactNode, useEffect, useRef, useState } from "react";
 import { useTranslation } from "react-i18next";
 import pac from "types-pac/pac.d.ts?raw";
 
+import { BaseLoadingOverlay } from "@/components/base";
 import { showNotice } from "@/services/noticeService";
 import { useThemeMode } from "@/services/states";
 import debounce from "@/utils/debounce";
@@ -42,12 +43,16 @@ interface LanguageSchemaMap {
 interface Props<T extends Language> {
   open: boolean;
   title?: string | ReactNode;
-  initialData: Promise<string>;
+  // Initial content loader: prefer passing a stable function. A plain Promise is supported,
+  // but it won't trigger background refreshes and should be paired with a stable `dataKey`.
+  initialData: Promise<string> | (() => Promise<string>);
+  // Logical document id; reloads when this or language/schema changes.
+  dataKey?: string | number;
   readOnly?: boolean;
   language: T;
   schema?: Schema<T>;
   onChange?: (prev?: string, curr?: string) => void;
-  onSave?: (prev?: string, curr?: string) => void;
+  onSave?: (prev?: string, curr?: string) => void | Promise<void>;
   onClose: () => void;
 }
 
@@ -55,7 +60,7 @@ let initialized = false;
 const monacoInitialization = () => {
   if (initialized) return;
 
-  // configure yaml worker
+  // YAML worker and schemas
   configureMonacoYaml(monaco, {
     validate: true,
     enableSchemaRequest: true,
@@ -74,7 +79,7 @@ const monacoInitialization = () => {
       },
     ],
   });
-  // configure PAC definition
+  // PAC type definitions for JS suggestions
   monaco.languages.typescript.javascriptDefaults.addExtraLib(pac, "pac.d.ts");
 
   initialized = true;
@@ -89,6 +94,7 @@ export const EditorViewer = <T extends Language>(props: Props<T>) => {
     open = false,
     title,
     initialData,
+    dataKey,
     readOnly = false,
     language = "yaml",
     schema,
@@ -98,39 +104,223 @@ export const EditorViewer = <T extends Language>(props: Props<T>) => {
   } = props;
 
   const resolvedTitle = title ?? t("profiles.components.menu.editFile");
-  const resolvedInitialData = useMemo(
-    () => initialData ?? Promise.resolve(""),
-    [initialData],
-  );
 
   const editorRef = useRef<monaco.editor.IStandaloneCodeEditor>(undefined);
   const prevData = useRef<string | undefined>("");
   const currData = useRef<string | undefined>("");
+  // Hold the latest loader without making effects depend on its identity
+  const initialDataRef = useRef<Props<T>["initialData"]>(initialData);
+  // Track mount/open state to prevent setState after unmount/close
+  const isMountedRef = useRef(true);
+  const openRef = useRef(open);
+  useEffect(() => {
+    openRef.current = open;
+  }, [open]);
+  useEffect(() => {
+    isMountedRef.current = true;
+    return () => {
+      isMountedRef.current = false;
+    };
+  }, []);
+  const [initialText, setInitialText] = useState<string | null>(null);
+  const [modelPath, setModelPath] = useState<string>("");
+  const modelChangeDisposableRef = useRef<monaco.IDisposable | null>(null);
+  // Unique per-component instance id to avoid shared Monaco models across dialogs
+  const instanceIdRef = useRef<string>(nanoid());
+  // Disable actions while loading or before modelPath is ready
+  const isLoading = initialText === null || !modelPath;
+  // Track if background refresh failed; offer a retry action in UI
+  const [refreshFailed, setRefreshFailed] = useState<unknown | null>(null);
+  // Skip the first background refresh triggered by [open, modelPath, dataKey]
+  // to avoid double-invoking the loader right after the initial load.
+  const skipNextRefreshRef = useRef(false);
+  // Monotonic token to cancel stale background refreshes
+  const reloadTokenRef = useRef(0);
+  // Track whether the editor has a usable baseline (either loaded or fallback).
+  // This avoids saving before the model/path are ready, while still allowing recovery
+  // when the initial load fails but an empty buffer is presented.
+  const [hasLoadedOnce, setHasLoadedOnce] = useState(false);
+  // Editor should only be read-only when explicitly requested by prop.
+  // A refresh/load failure must not lock the editor to allow manual recovery.
+  const effectiveReadOnly = readOnly;
+  // Keep ref in sync with prop without triggering loads
+  useEffect(() => {
+    initialDataRef.current = initialData;
+  }, [initialData]);
+  // Background refresh: when the dialog/model is ready and the underlying resource key changes,
+  // try to refresh content (only if user hasn't typed). Do NOT depend on `initialData` function
+  // identity because callers often pass inline lambdas that change every render.
+  useEffect(() => {
+    if (!open) return;
+    // Only attempt after initial model is ready to avoid racing the initial load
+    if (!modelPath) return;
+    // Avoid immediate double-load on open: the initial load has just completed.
+    if (skipNextRefreshRef.current) {
+      skipNextRefreshRef.current = false;
+      return;
+    }
+    // Only meaningful when a callable loader is provided (plain Promise cannot be "recalled")
+    if (typeof initialDataRef.current === "function") {
+      void reloadLatest();
+    }
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [open, modelPath, dataKey]);
+  // Helper to (soft) reload latest source and apply only if the user hasn't typed yet
+  const reloadLatest = useLockFn(async () => {
+    // Snapshot the model/doc identity and bump a token so older calls can't win
+    const myToken = ++reloadTokenRef.current;
+    const expectedModelPath = modelPath;
+    const expectedKey = dataKey;
+    if (isMountedRef.current && openRef.current) {
+      // Clear previous error (UI hint) at the start of a new attempt
+      setRefreshFailed(null);
+    }
+    try {
+      const src = initialDataRef.current;
+      const promise =
+        typeof src === "function"
+          ? (src as () => Promise<string>)()
+          : (src ?? Promise.resolve(""));
+      const next = await promise;
+      // Abort if component/dialog state changed meanwhile:
+      // - unmounted or closed
+      // - document switched (modelPath/dataKey no longer match)
+      // - a newer reload was started
+      if (
+        !isMountedRef.current ||
+        !openRef.current ||
+        expectedModelPath !== modelPath ||
+        expectedKey !== dataKey ||
+        myToken !== reloadTokenRef.current
+      ) {
+        return;
+      }
+      // Only update when untouched and value changed
+      const userUntouched = currData.current === prevData.current;
+      if (userUntouched && next !== prevData.current) {
+        prevData.current = next;
+        currData.current = next;
+        editorRef.current?.setValue(next);
+      }
+      // Ensure any previous error state is cleared after a successful refresh
+      if (isMountedRef.current && openRef.current) {
+        setRefreshFailed(null);
+      }
+      // If we previously failed to load, a successful refresh establishes a valid baseline
+      if (isMountedRef.current && openRef.current) {
+        setHasLoadedOnce(true);
+      }
+    } catch (err) {
+      // Only report if still mounted/open and this call is the latest
+      if (
+        isMountedRef.current &&
+        openRef.current &&
+        myToken === reloadTokenRef.current
+      ) {
+        setRefreshFailed(err ?? true);
+        showNotice.error(
+          "shared.feedback.notifications.common.refreshFailed",
+          err,
+        );
+      }
+    }
+  });
 
   const beforeMount = () => {
-    monacoInitialization(); // initialize monaco
+    monacoInitialization();
   };
 
+  // Prepare initial content and a stable model path for monaco-react
+  /* eslint-disable @eslint-react/hooks-extra/no-direct-set-state-in-use-effect */
+  useEffect(() => {
+    if (!open) return;
+    let cancelled = false;
+    // Clear state up-front to avoid showing stale content while loading
+    setInitialText(null);
+    setModelPath("");
+    // Clear any stale refresh error when starting a new load
+    setRefreshFailed(null);
+    // Reset initial-load success flag on open/start
+    setHasLoadedOnce(false);
+    // We will perform an explicit initial load below; skip the first background refresh.
+    skipNextRefreshRef.current = true;
+    prevData.current = undefined;
+    currData.current = undefined;
+
+    (async () => {
+      try {
+        const dataSource = initialDataRef.current;
+        const dataPromise =
+          typeof dataSource === "function"
+            ? (dataSource as () => Promise<string>)()
+            : (dataSource ?? Promise.resolve(""));
+        const data = await dataPromise;
+        if (cancelled) return;
+        prevData.current = data;
+        currData.current = data;
+
+        setInitialText(data);
+        // Build a path that matches YAML schemas when applicable, and avoids "undefined" in name
+        const pathParts = [String(dataKey ?? nanoid()), instanceIdRef.current];
+        if (schema) pathParts.push(String(schema));
+        pathParts.push(language);
+
+        setModelPath(pathParts.join("."));
+        // Successful initial load should clear any previous refresh error flag
+        setRefreshFailed(null);
+        // Mark that we have a valid baseline content
+        setHasLoadedOnce(true);
+      } catch (err) {
+        if (cancelled) return;
+        // Notify the error and still show an empty editor so the user isn't stuck
+        showNotice.error(err);
+
+        // Align refs with fallback text after a load failure
+        prevData.current = "";
+        currData.current = "";
+
+        setInitialText("");
+        const pathParts = [String(dataKey ?? nanoid()), instanceIdRef.current];
+        if (schema) pathParts.push(String(schema));
+        pathParts.push(language);
+
+        setModelPath(pathParts.join("."));
+        // Mark refresh failure so users can retry
+        setRefreshFailed(err ?? true);
+        // Initial load failed; keep `hasLoadedOnce` false to prevent accidental save
+        // of an empty buffer. It will be enabled on successful refresh or first edit.
+        setHasLoadedOnce(false);
+      }
+    })();
+
+    return () => {
+      cancelled = true;
+    };
+  }, [open, dataKey, language, schema]);
+  /* eslint-enable @eslint-react/hooks-extra/no-direct-set-state-in-use-effect */
+
   const onMount = async (editor: monaco.editor.IStandaloneCodeEditor) => {
     editorRef.current = editor;
-
-    // retrieve initial data
-    await resolvedInitialData.then((data) => {
-      prevData.current = data;
-      currData.current = data;
-
-      // create and set model
-      const uri = monaco.Uri.parse(`${nanoid()}.${schema}.${language}`);
-      const model = monaco.editor.createModel(data, language, uri);
-      editorRef.current?.setModel(model);
+    // Dispose previous model when switching (monaco-react creates a fresh model when `path` changes)
+    modelChangeDisposableRef.current?.dispose();
+    modelChangeDisposableRef.current = editor.onDidChangeModel((e) => {
+      if (e.oldModelUrl) {
+        const oldModel = monaco.editor.getModel(e.oldModelUrl);
+        oldModel?.dispose();
+      }
     });
+    // No refresh on mount; doing so would double-load.
+    // Background refreshes are handled by the [open, modelPath, dataKey] effect.
   };
 
-  const handleChange = useLockFn(async (_value?: string) => {
+  const handleChange = useLockFn(async (value?: string) => {
     try {
-      const value = editorRef.current?.getValue();
-      currData.current = value;
+      currData.current = value ?? editorRef.current?.getValue();
       onChange?.(prevData.current, currData.current);
+      // If the initial load failed, allow saving after the user makes an edit.
+      if (!hasLoadedOnce) {
+        setHasLoadedOnce(true);
+      }
     } catch (err) {
       showNotice.error(err);
     }
@@ -138,9 +328,18 @@ export const EditorViewer = <T extends Language>(props: Props<T>) => {
 
   const handleSave = useLockFn(async () => {
     try {
-      if (!readOnly) {
-        currData.current = editorRef.current?.getValue();
-        onSave?.(prevData.current, currData.current);
+      // Disallow saving if initial content never loaded successfully to avoid accidental overwrite
+      if (!readOnly && hasLoadedOnce) {
+        // Guard: if the editor/model hasn't mounted, bail out
+        if (!editorRef.current) {
+          return;
+        }
+        currData.current = editorRef.current.getValue();
+        if (onSave) {
+          await onSave(prevData.current, currData.current);
+          // If save succeeds, align prev with current
+          prevData.current = currData.current;
+        }
       }
       onClose();
     } catch (err) {
@@ -156,30 +355,30 @@ export const EditorViewer = <T extends Language>(props: Props<T>) => {
     }
   });
 
-  const editorResize = useMemo(
-    () =>
-      debounce(() => {
-        editorRef.current?.layout();
-        setTimeout(() => editorRef.current?.layout(), 500);
-      }, 100),
-    [],
-  );
-
   useEffect(() => {
     const onResized = debounce(() => {
-      editorResize();
-      appWindow.isMaximized().then((maximized) => {
-        setIsMaximized(() => maximized);
-      });
+      appWindow
+        .isMaximized()
+        .then((maximized) => setIsMaximized(() => maximized));
+      // Ensure Monaco recalculates layout after window resize/maximize/restore.
+      // automaticLayout is not always sufficient when the parent dialog resizes.
+      try {
+        editorRef.current?.layout();
+      } catch {}
     }, 100);
     const unlistenResized = appWindow.onResized(onResized);
 
     return () => {
       unlistenResized.then((fn) => fn());
+      // Clean up editor and model to avoid leaks
+      const model = editorRef.current?.getModel();
       editorRef.current?.dispose();
+      model?.dispose();
+      modelChangeDisposableRef.current?.dispose();
+      modelChangeDisposableRef.current = null;
       editorRef.current = undefined;
     };
-  }, [editorResize]);
+  }, []);
 
   return (
     <Dialog open={open} onClose={onClose} maxWidth="xl" fullWidth>
@@ -188,42 +387,94 @@ export const EditorViewer = <T extends Language>(props: Props<T>) => {
       <DialogContent
         sx={{
           width: "auto",
+          // Give the editor a scrollable height (even in nested dialogs)
           height: "calc(100vh - 185px)",
+          display: "flex",
+          flexDirection: "column",
           overflow: "hidden",
         }}
       >
-        <MonacoEditor
-          language={language}
-          theme={themeMode === "light" ? "light" : "vs-dark"}
-          options={{
-            tabSize: ["yaml", "javascript", "css"].includes(language) ? 2 : 4, // 根据语言类型设置缩进大小
-            minimap: {
-              enabled: document.documentElement.clientWidth >= 1500, // 超过一定宽度显示minimap滚动条
-            },
-            mouseWheelZoom: true, // 按住Ctrl滚轮调节缩放比例
-            readOnly: readOnly, // 只读模式
-            readOnlyMessage: {
-              value: t("profiles.modals.editor.messages.readOnly"),
-            }, // 只读模式尝试编辑时的提示信息
-            renderValidationDecorations: "on", // 只读模式下显示校验信息
-            quickSuggestions: {
-              strings: true, // 字符串类型的建议
-              comments: true, // 注释类型的建议
-              other: true, // 其他类型的建议
-            },
-            padding: {
-              top: 33, // 顶部padding防止遮挡snippets
-            },
-            fontFamily: `Fira Code, JetBrains Mono, Roboto Mono, "Source Code Pro", Consolas, Menlo, Monaco, monospace, "Courier New", "Apple Color Emoji"${
-              getSystem() === "windows" ? ", twemoji mozilla" : ""
-            }`,
-            fontLigatures: false, // 连字符
-            smoothScrolling: true, // 平滑滚动
-          }}
-          beforeMount={beforeMount}
-          onMount={onMount}
-          onChange={handleChange}
-        />
+        <div style={{ position: "relative", flex: "1 1 auto", minHeight: 0 }}>
+          {/* Show overlay while loading or until modelPath is ready */}
+          <BaseLoadingOverlay isLoading={isLoading} />
+          {/* Background refresh failure helper */}
+          {!!refreshFailed && (
+            <div
+              style={{
+                position: "absolute",
+                top: 8,
+                right: 10,
+                zIndex: 2,
+                display: "flex",
+                gap: 8,
+                alignItems: "center",
+                pointerEvents: "auto",
+              }}
+            >
+              <span
+                style={{
+                  color: "var(--mui-palette-warning-main, #ed6c02)",
+                  background: "rgba(237,108,2,0.1)",
+                  border: "1px solid rgba(237,108,2,0.35)",
+                  borderRadius: 6,
+                  padding: "2px 8px",
+                  fontSize: 12,
+                  lineHeight: "20px",
+                  userSelect: "text",
+                }}
+              >
+                {t("shared.feedback.notifications.common.refreshFailed")}
+              </span>
+              <Button
+                size="small"
+                variant="outlined"
+                onClick={() => reloadLatest()}
+              >
+                {t("shared.actions.retry")}
+              </Button>
+            </div>
+          )}
+          {initialText !== null && modelPath && (
+            <MonacoEditor
+              height="100%"
+              path={modelPath}
+              language={language}
+              defaultValue={initialText}
+              theme={themeMode === "light" ? "light" : "vs-dark"}
+              options={{
+                automaticLayout: true,
+                tabSize: ["yaml", "javascript", "css"].includes(language)
+                  ? 2
+                  : 4,
+                minimap: {
+                  enabled: document.documentElement.clientWidth >= 1500,
+                },
+                mouseWheelZoom: true,
+                readOnly: effectiveReadOnly,
+                readOnlyMessage: {
+                  value: t("profiles.modals.editor.messages.readOnly"),
+                },
+                renderValidationDecorations: "on",
+                quickSuggestions: {
+                  strings: true,
+                  comments: true,
+                  other: true,
+                },
+                padding: {
+                  top: 33, // Top padding to prevent snippet overlap
+                },
+                fontFamily: `Fira Code, JetBrains Mono, Roboto Mono, "Source Code Pro", Consolas, Menlo, Monaco, monospace, "Courier New", "Apple Color Emoji"${
+                  getSystem() === "windows" ? ", twemoji mozilla" : ""
+                }`,
+                fontLigatures: false,
+                smoothScrolling: true,
+              }}
+              beforeMount={beforeMount}
+              onMount={onMount}
+              onChange={handleChange}
+            />
+          )}
+        </div>
 
         <ButtonGroup
           variant="contained"
@@ -234,6 +485,7 @@ export const EditorViewer = <T extends Language>(props: Props<T>) => {
             color="inherit"
             sx={{ display: readOnly ? "none" : "" }}
             title={t("profiles.modals.editor.actions.format")}
+            disabled={isLoading}
             onClick={() =>
               editorRef.current
                 ?.getAction("editor.action.formatDocument")
@@ -248,7 +500,21 @@ export const EditorViewer = <T extends Language>(props: Props<T>) => {
             title={t(
               isMaximized ? "shared.window.minimize" : "shared.window.maximize",
             )}
-            onClick={() => appWindow.toggleMaximize().then(editorResize)}
+            onClick={() =>
+              appWindow
+                .toggleMaximize()
+                .then(() =>
+                  appWindow
+                    .isMaximized()
+                    .then((maximized) => setIsMaximized(maximized)),
+                )
+                .finally(() => {
+                  // Nudge a layout in case the resize event batching lags behind
+                  try {
+                    editorRef.current?.layout();
+                  } catch {}
+                })
+            }
           >
             {isMaximized ? <CloseFullscreenRounded /> : <OpenInFullRounded />}
           </IconButton>
@@ -260,7 +526,11 @@ export const EditorViewer = <T extends Language>(props: Props<T>) => {
           {t(readOnly ? "shared.actions.close" : "shared.actions.cancel")}
         </Button>
         {!readOnly && (
-          <Button onClick={handleSave} variant="contained">
+          <Button
+            onClick={handleSave}
+            variant="contained"
+            disabled={isLoading || !hasLoadedOnce}
+          >
             {t("shared.actions.save")}
           </Button>
         )}
diff --git a/src/components/profile/profile-item.tsx b/src/components/profile/profile-item.tsx
index 7f928336d..eb5c68388 100644
--- a/src/components/profile/profile-item.tsx
+++ b/src/components/profile/profile-item.tsx
@@ -830,7 +830,8 @@ export const ProfileItem = (props: Props) => {
       {fileOpen && (
         <EditorViewer
           open={true}
-          initialData={readProfileFile(uid)}
+          initialData={() => readProfileFile(uid)}
+          dataKey={uid}
           language="yaml"
           schema="clash"
           onSave={async (prev, curr) => {
@@ -876,9 +877,10 @@ export const ProfileItem = (props: Props) => {
       {mergeOpen && (
         <EditorViewer
           open={true}
-          initialData={readProfileFile(option?.merge ?? "")}
+          initialData={() => readProfileFile(option?.merge ?? "")}
+          dataKey={`merge:${option?.merge ?? ""}`}
           language="yaml"
-          schema="clash"
+          schema="merge"
           onSave={async (prev, curr) => {
             await saveProfileFile(option?.merge ?? "", curr ?? "");
             onSave?.(prev, curr);
@@ -889,7 +891,8 @@ export const ProfileItem = (props: Props) => {
       {scriptOpen && (
         <EditorViewer
           open={true}
-          initialData={readProfileFile(option?.script ?? "")}
+          initialData={() => readProfileFile(option?.script ?? "")}
+          dataKey={`script:${option?.script ?? ""}`}
           language="javascript"
           onSave={async (prev, curr) => {
             await saveProfileFile(option?.script ?? "", curr ?? "");
diff --git a/src/components/profile/profile-more.tsx b/src/components/profile/profile-more.tsx
index bcc7acd34..896d54e67 100644
--- a/src/components/profile/profile-more.tsx
+++ b/src/components/profile/profile-more.tsx
@@ -181,9 +181,10 @@ export const ProfileMore = (props: Props) => {
         <EditorViewer
           open={true}
           title={t(globalTitles[id])}
-          initialData={readProfileFile(id)}
+          initialData={() => readProfileFile(id)}
+          dataKey={id}
           language={id === "Merge" ? "yaml" : "javascript"}
-          schema={id === "Merge" ? "clash" : undefined}
+          schema={id === "Merge" ? "merge" : undefined}
           onSave={async (prev, curr) => {
             await saveProfileFile(id, curr ?? "");
             onSave?.(prev, curr);
diff --git a/src/components/setting/mods/config-viewer.tsx b/src/components/setting/mods/config-viewer.tsx
index 564a56dcc..d10ed2001 100644
--- a/src/components/setting/mods/config-viewer.tsx
+++ b/src/components/setting/mods/config-viewer.tsx
@@ -31,7 +31,8 @@ export const ConfigViewer = forwardRef<DialogRef>((_, ref) => {
           <Chip label={t("shared.labels.readOnly")} size="small" />
         </Box>
       }
-      initialData={Promise.resolve(runtimeConfig)}
+      initialData={() => Promise.resolve(runtimeConfig)}
+      dataKey="runtime-config"
       readOnly
       language="yaml"
       schema="clash"
diff --git a/src/components/setting/mods/sysproxy-viewer.tsx b/src/components/setting/mods/sysproxy-viewer.tsx
index 3d2b0f37a..5208c42b0 100644
--- a/src/components/setting/mods/sysproxy-viewer.tsx
+++ b/src/components/setting/mods/sysproxy-viewer.tsx
@@ -617,7 +617,8 @@ export const SysproxyViewer = forwardRef<DialogRef>((props, ref) => {
               <EditorViewer
                 open={true}
                 title={t("settings.modals.sysproxy.actions.editPac")}
-                initialData={Promise.resolve(value.pac_content ?? "")}
+                initialData={() => Promise.resolve(value.pac_content ?? "")}
+                dataKey="sysproxy-pac"
                 language="javascript"
                 onSave={(_prev, curr) => {
                   let pac = DEFAULT_PAC;
diff --git a/src/components/setting/mods/theme-viewer.tsx b/src/components/setting/mods/theme-viewer.tsx
index b9f52a800..0f07f4ccc 100644
--- a/src/components/setting/mods/theme-viewer.tsx
+++ b/src/components/setting/mods/theme-viewer.tsx
@@ -9,7 +9,14 @@ import {
   useTheme,
 } from "@mui/material";
 import { useLockFn } from "ahooks";
-import { useImperativeHandle, useMemo, useState } from "react";
+import {
+  useEffect,
+  useImperativeHandle,
+  useMemo,
+  useRef,
+  useState,
+  useCallback,
+} from "react";
 import { useTranslation } from "react-i18next";
 
 import { BaseDialog, DialogRef } from "@/components/base";
@@ -27,6 +34,11 @@ export function ThemeViewer(props: { ref?: React.Ref<DialogRef> }) {
   const { verge, patchVerge } = useVerge();
   const { theme_setting } = verge ?? {};
   const [theme, setTheme] = useState(theme_setting || {});
+  // Latest theme ref to avoid stale closures when saving CSS
+  const themeRef = useRef(theme);
+  useEffect(() => {
+    themeRef.current = theme;
+  }, [theme]);
 
   useImperativeHandle(ref, () => ({
     open: () => {
@@ -55,7 +67,6 @@ export function ThemeViewer(props: { ref?: React.Ref<DialogRef> }) {
     }
   });
 
-  // default theme
   const { palette } = useTheme();
 
   const dt = palette.mode === "light" ? defaultTheme : defaultDarkTheme;
@@ -100,6 +111,13 @@ export function ThemeViewer(props: { ref?: React.Ref<DialogRef> }) {
     [],
   );
 
+  // Stable loader that returns a fresh Promise each call so EditorViewer
+  // can retry/refresh and always read the latest staged CSS from state.
+  const loadCss = useCallback(
+    () => Promise.resolve(themeRef.current?.css_injection ?? ""),
+    [],
+  );
+
   const renderItem = (labelKey: string, key: ThemeKey) => {
     const label = t(labelKey);
     return (
@@ -159,11 +177,15 @@ export function ThemeViewer(props: { ref?: React.Ref<DialogRef> }) {
             <EditorViewer
               open={true}
               title={t("settings.components.verge.theme.dialogs.editCssTitle")}
-              initialData={Promise.resolve(theme.css_injection ?? "")}
+              initialData={loadCss}
+              dataKey="theme-css"
               language="css"
-              onSave={(_prev, curr) => {
-                theme.css_injection = curr;
-                handleChange("css_injection");
+              onSave={async (_prev, curr) => {
+                // Only stage the CSS change locally. Persistence happens
+                // when the outer Theme dialog's Save button is pressed.
+                const prevTheme = themeRef.current || {};
+                const nextCss = curr ?? "";
+                setTheme({ ...prevTheme, css_injection: nextCss });
               }}
               onClose={() => {
                 setEditorOpen(false);
diff --git a/src/locales/ar/shared.json b/src/locales/ar/shared.json
index 9c4d4489b..5ef8d4f1f 100644
--- a/src/locales/ar/shared.json
+++ b/src/locales/ar/shared.json
@@ -89,7 +89,8 @@
       "common": {
         "copySuccess": "تم النسخ بنجاح",
         "saveSuccess": "Configuration saved successfully",
-        "saveFailed": "Failed to save configuration"
+        "saveFailed": "Failed to save configuration",
+        "refreshFailed": "فشل التحديث"
       }
     },
     "validation": {
diff --git a/src/locales/de/shared.json b/src/locales/de/shared.json
index eb2e34d7d..69faa3a6e 100644
--- a/src/locales/de/shared.json
+++ b/src/locales/de/shared.json
@@ -89,7 +89,8 @@
       "common": {
         "copySuccess": "Kopieren erfolgreich",
         "saveSuccess": "Zufalls-Konfiguration erfolgreich gespeichert",
-        "saveFailed": "Failed to save configuration"
+        "saveFailed": "Failed to save configuration",
+        "refreshFailed": "Aktualisierung fehlgeschlagen"
       }
     },
     "validation": {
diff --git a/src/locales/en/shared.json b/src/locales/en/shared.json
index 1e2f61317..e27052384 100644
--- a/src/locales/en/shared.json
+++ b/src/locales/en/shared.json
@@ -89,7 +89,8 @@
       "common": {
         "copySuccess": "Copy Success",
         "saveSuccess": "Configuration saved successfully",
-        "saveFailed": "Failed to save configuration"
+        "saveFailed": "Failed to save configuration",
+        "refreshFailed": "Refresh failed; showing last loaded value"
       }
     },
     "validation": {
diff --git a/src/locales/es/shared.json b/src/locales/es/shared.json
index 7ed7494c6..7babab4ef 100644
--- a/src/locales/es/shared.json
+++ b/src/locales/es/shared.json
@@ -89,7 +89,8 @@
       "common": {
         "copySuccess": "Copia exitosa",
         "saveSuccess": "Configuración aleatoria guardada correctamente",
-        "saveFailed": "Failed to save configuration"
+        "saveFailed": "Failed to save configuration",
+        "refreshFailed": "Error al actualizar"
       }
     },
     "validation": {
diff --git a/src/locales/fa/shared.json b/src/locales/fa/shared.json
index 6ab4e72d0..458405075 100644
--- a/src/locales/fa/shared.json
+++ b/src/locales/fa/shared.json
@@ -89,7 +89,8 @@
       "common": {
         "copySuccess": "کپی با موفقیت انجام شد",
         "saveSuccess": "Configuration saved successfully",
-        "saveFailed": "Failed to save configuration"
+        "saveFailed": "Failed to save configuration",
+        "refreshFailed": "به‌روزرسانی ناموفق بود"
       }
     },
     "validation": {
diff --git a/src/locales/id/shared.json b/src/locales/id/shared.json
index 057e9f74b..0effab311 100644
--- a/src/locales/id/shared.json
+++ b/src/locales/id/shared.json
@@ -89,7 +89,8 @@
       "common": {
         "copySuccess": "Salin Berhasil",
         "saveSuccess": "Configuration saved successfully",
-        "saveFailed": "Failed to save configuration"
+        "saveFailed": "Failed to save configuration",
+        "refreshFailed": "Penyegaran gagal"
       }
     },
     "validation": {
diff --git a/src/locales/jp/shared.json b/src/locales/jp/shared.json
index 292e7c1b2..20a88547c 100644
--- a/src/locales/jp/shared.json
+++ b/src/locales/jp/shared.json
@@ -89,7 +89,8 @@
       "common": {
         "copySuccess": "コピー成功",
         "saveSuccess": "ランダム設定を保存完了",
-        "saveFailed": "Failed to save configuration"
+        "saveFailed": "Failed to save configuration",
+        "refreshFailed": "更新に失敗しました"
       }
     },
     "validation": {
diff --git a/src/locales/ko/shared.json b/src/locales/ko/shared.json
index 4309e5f9c..13877c0e1 100644
--- a/src/locales/ko/shared.json
+++ b/src/locales/ko/shared.json
@@ -89,7 +89,8 @@
       "common": {
         "copySuccess": "복사 성공",
         "saveSuccess": "설정이 저장되었습니다",
-        "saveFailed": "설정 저장 실패"
+        "saveFailed": "설정 저장 실패",
+        "refreshFailed": "새로고침 실패"
       }
     },
     "validation": {
diff --git a/src/locales/ru/shared.json b/src/locales/ru/shared.json
index be79ca589..573de6d2f 100644
--- a/src/locales/ru/shared.json
+++ b/src/locales/ru/shared.json
@@ -89,7 +89,8 @@
       "common": {
         "copySuccess": "Скопировано",
         "saveSuccess": "Configuration saved successfully",
-        "saveFailed": "Failed to save configuration"
+        "saveFailed": "Failed to save configuration",
+        "refreshFailed": "Не удалось обновить"
       }
     },
     "validation": {
diff --git a/src/locales/tr/shared.json b/src/locales/tr/shared.json
index e094bdbc2..eeac37355 100644
--- a/src/locales/tr/shared.json
+++ b/src/locales/tr/shared.json
@@ -89,7 +89,8 @@
       "common": {
         "copySuccess": "Kopyalama Başarılı",
         "saveSuccess": "Configuration saved successfully",
-        "saveFailed": "Failed to save configuration"
+        "saveFailed": "Failed to save configuration",
+        "refreshFailed": "Yenileme başarısız"
       }
     },
     "validation": {
diff --git a/src/locales/tt/shared.json b/src/locales/tt/shared.json
index 9405b43ac..eb6316b33 100644
--- a/src/locales/tt/shared.json
+++ b/src/locales/tt/shared.json
@@ -89,7 +89,8 @@
       "common": {
         "copySuccess": "Күчерелде",
         "saveSuccess": "Configuration saved successfully",
-        "saveFailed": "Failed to save configuration"
+        "saveFailed": "Failed to save configuration",
+        "refreshFailed": "Refresh failed"
       }
     },
     "validation": {
diff --git a/src/locales/zh/shared.json b/src/locales/zh/shared.json
index 7db791f85..047ce8186 100644
--- a/src/locales/zh/shared.json
+++ b/src/locales/zh/shared.json
@@ -89,7 +89,8 @@
       "common": {
         "copySuccess": "复制成功",
         "saveSuccess": "配置保存成功",
-        "saveFailed": "配置保存失败"
+        "saveFailed": "配置保存失败",
+        "refreshFailed": "刷新失败"
       }
     },
     "validation": {
diff --git a/src/locales/zhtw/shared.json b/src/locales/zhtw/shared.json
index c7d5fe72c..089591055 100644
--- a/src/locales/zhtw/shared.json
+++ b/src/locales/zhtw/shared.json
@@ -89,7 +89,8 @@
       "common": {
         "copySuccess": "複製成功",
         "saveSuccess": "設定儲存完成",
-        "saveFailed": "設定儲存失敗"
+        "saveFailed": "設定儲存失敗",
+        "refreshFailed": "重整失敗"
       }
     },
     "validation": {
diff --git a/src/types/generated/i18n-keys.ts b/src/types/generated/i18n-keys.ts
index ed28c0e8a..5f1c376b1 100644
--- a/src/types/generated/i18n-keys.ts
+++ b/src/types/generated/i18n-keys.ts
@@ -706,6 +706,7 @@ export const translationKeys = [
   "shared.feedback.notifications.common.copySuccess",
   "shared.feedback.notifications.common.saveSuccess",
   "shared.feedback.notifications.common.saveFailed",
+  "shared.feedback.notifications.common.refreshFailed",
   "shared.feedback.validation.config.failed",
   "shared.feedback.validation.config.bootFailed",
   "shared.feedback.validation.config.coreChangeFailed",
diff --git a/src/types/generated/i18n-resources.ts b/src/types/generated/i18n-resources.ts
index e64659cea..225338e1e 100644
--- a/src/types/generated/i18n-resources.ts
+++ b/src/types/generated/i18n-resources.ts
@@ -1200,6 +1200,7 @@ export interface TranslationResources {
         notifications: {
           common: {
             copySuccess: string;
+            refreshFailed: string;
             saveFailed: string;
             saveSuccess: string;
           };