diff --git a/src/main/app-controller.ts b/src/main/app-controller.ts
index 2fa849d..ef07281 100644
--- a/src/main/app-controller.ts
+++ b/src/main/app-controller.ts
@@ -70,11 +70,17 @@ export class AppController {
   }
 
   public updateSettings(partial: Partial<AppSettings>): AppSettings {
-    this.settings = normalizeSettings({
+    const nextSettings = normalizeSettings({
       ...defaultSettings(),
       ...this.settings,
       ...partial
     });
+
+    if (JSON.stringify(nextSettings) === JSON.stringify(this.settings)) {
+      return this.settings;
+    }
+
+    this.settings = nextSettings;
     saveSettings(this.storagePaths, this.settings);
     this.manager.setSettings(this.settings);
     return this.settings;
diff --git a/src/renderer/App.tsx b/src/renderer/App.tsx
index a85013a..bc613b4 100644
--- a/src/renderer/App.tsx
+++ b/src/renderer/App.tsx
@@ -1,4 +1,4 @@
-import { DragEvent, KeyboardEvent, ReactElement, useCallback, useEffect, useMemo, useRef, useState } from "react";
+import { DragEvent, KeyboardEvent, ReactElement, useCallback, useDeferredValue, useEffect, useMemo, useRef, useState } from "react";
 import type { AppSettings, AppTheme, BandwidthScheduleEntry, DebridFallbackProvider, DebridProvider, DownloadItem, DownloadStats, PackageEntry, UiSnapshot, UpdateCheckResult } from "../shared/types";
 
 type Tab = "collector" | "downloads" | "settings";
@@ -66,6 +66,8 @@ export function App(): ReactElement {
   const [tab, setTab] = useState<Tab>("collector");
   const [statusToast, setStatusToast] = useState("");
   const [settingsDraft, setSettingsDraft] = useState<AppSettings>(emptySnapshot().settings);
+  const [settingsDirty, setSettingsDirty] = useState(false);
+  const settingsDirtyRef = useRef(false);
   const latestStateRef = useRef<UiSnapshot | null>(null);
   const stateFlushTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
   const toastTimerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
@@ -81,7 +83,9 @@ export function App(): ReactElement {
   const [collapsedPackages, setCollapsedPackages] = useState<Record<string, boolean>>({});
   const [downloadSearch, setDownloadSearch] = useState("");
   const [actionBusy, setActionBusy] = useState(false);
+  const actionBusyRef = useRef(false);
   const dragOverRef = useRef(false);
+  const dragDepthRef = useRef(0);
 
   const currentCollectorTab = collectorTabs.find((t) => t.id === activeCollectorTab) ?? collectorTabs[0];
 
@@ -89,6 +93,10 @@ export function App(): ReactElement {
     activeCollectorTabRef.current = activeCollectorTab;
   }, [activeCollectorTab]);
 
+  useEffect(() => {
+    settingsDirtyRef.current = settingsDirty;
+  }, [settingsDirty]);
+
   const showToast = (message: string, timeoutMs = 2200): void => {
     setStatusToast(message);
     if (toastTimerRef.current) { clearTimeout(toastTimerRef.current); }
@@ -104,6 +112,7 @@ export function App(): ReactElement {
     void window.rd.getSnapshot().then((state) => {
       setSnapshot(state);
       setSettingsDraft(state.settings);
+      setSettingsDirty(false);
       applyTheme(state.settings.theme);
       if (state.settings.autoUpdateCheck) {
         void window.rd.checkUpdates().then((result) => {
@@ -119,7 +128,11 @@ export function App(): ReactElement {
       stateFlushTimerRef.current = setTimeout(() => {
         stateFlushTimerRef.current = null;
         if (latestStateRef.current) {
-          setSnapshot(latestStateRef.current);
+          const next = latestStateRef.current;
+          setSnapshot(next);
+          if (!settingsDirtyRef.current) {
+            setSettingsDraft(next.settings);
+          }
           latestStateRef.current = null;
         }
       }, 220);
@@ -145,23 +158,28 @@ export function App(): ReactElement {
     .map((id: string) => snapshot.session.packages[id])
     .filter(Boolean), [snapshot]);
 
+  const packageOrderKey = useMemo(() => snapshot.session.packageOrder.join("|"), [snapshot.session.packageOrder]);
+
   useEffect(() => {
     setCollapsedPackages((prev) => {
       const next: Record<string, boolean> = {};
-      for (const pkg of packages) {
-        next[pkg.id] = prev[pkg.id] ?? false;
+      const defaultCollapsed = snapshot.session.packageOrder.length >= 24;
+      for (const packageId of snapshot.session.packageOrder) {
+        next[packageId] = prev[packageId] ?? defaultCollapsed;
       }
       return next;
     });
-  }, [packages]);
+  }, [packageOrderKey, snapshot.session.packageOrder.length]);
+
+  const deferredDownloadSearch = useDeferredValue(downloadSearch);
 
   const filteredPackages = useMemo(() => {
-    const query = downloadSearch.trim().toLowerCase();
+    const query = deferredDownloadSearch.trim().toLowerCase();
     if (!query) {
       return packages;
     }
     return packages.filter((pkg) => pkg.name.toLowerCase().includes(query));
-  }, [packages, downloadSearch]);
+  }, [packages, deferredDownloadSearch]);
 
   const allPackagesCollapsed = useMemo(() => (
     packages.length > 0 && packages.every((pkg) => collapsedPackages[pkg.id])
@@ -250,6 +268,7 @@ export function App(): ReactElement {
     try {
       const result = await window.rd.updateSettings(normalizedSettingsDraft);
       setSettingsDraft(result);
+      setSettingsDirty(false);
       applyTheme(result.theme);
       showToast("Einstellungen gespeichert", 1800);
     } catch (error) { showToast(`Einstellungen konnten nicht gespeichert werden: ${String(error)}`, 2800); }
@@ -285,6 +304,7 @@ export function App(): ReactElement {
 
   const onDrop = async (event: DragEvent<HTMLElement>): Promise<void> => {
     event.preventDefault();
+    dragDepthRef.current = 0;
     dragOverRef.current = false;
     setDragOver(false);
     const files = Array.from(event.dataTransfer.files ?? []) as File[];
@@ -338,18 +358,29 @@ export function App(): ReactElement {
     } catch (error) { showToast(`Import fehlgeschlagen: ${String(error)}`, 2600); }
   };
 
-  const setBool = (key: keyof AppSettings, value: boolean): void => { setSettingsDraft((prev) => ({ ...prev, [key]: value })); };
-  const setText = (key: keyof AppSettings, value: string): void => { setSettingsDraft((prev) => ({ ...prev, [key]: value })); };
-  const setNum = (key: keyof AppSettings, value: number): void => { setSettingsDraft((prev) => ({ ...prev, [key]: value })); };
+  const setBool = (key: keyof AppSettings, value: boolean): void => {
+    setSettingsDirty(true);
+    setSettingsDraft((prev) => ({ ...prev, [key]: value }));
+  };
+  const setText = (key: keyof AppSettings, value: string): void => {
+    setSettingsDirty(true);
+    setSettingsDraft((prev) => ({ ...prev, [key]: value }));
+  };
+  const setNum = (key: keyof AppSettings, value: number): void => {
+    setSettingsDirty(true);
+    setSettingsDraft((prev) => ({ ...prev, [key]: value }));
+  };
   const setSpeedLimitMbps = (value: number): void => {
     const mbps = Number.isFinite(value) ? Math.max(0, value) : 0;
+    setSettingsDirty(true);
     setSettingsDraft((prev) => ({ ...prev, speedLimitKbps: Math.floor(mbps * 1024) }));
   };
 
   const performQuickAction = async (action: () => Promise<unknown>): Promise<void> => {
-    if (actionBusy) {
+    if (actionBusyRef.current) {
       return;
     }
+    actionBusyRef.current = true;
     setActionBusy(true);
     try {
       await action();
@@ -357,8 +388,9 @@ export function App(): ReactElement {
       showToast(`Fehler: ${String(error)}`, 2600);
     } finally {
       setTimeout(() => {
+        actionBusyRef.current = false;
         setActionBusy(false);
-      }, 100);
+      }, 80);
     }
   };
 
@@ -464,15 +496,20 @@ export function App(): ReactElement {
   return (
     <div
       className={`app-shell${dragOver ? " drag-over" : ""}`}
-      onDragOver={(e) => {
-        e.preventDefault();
+      onDragEnter={(event) => {
+        event.preventDefault();
+        dragDepthRef.current += 1;
         if (!dragOverRef.current) {
           dragOverRef.current = true;
           setDragOver(true);
         }
       }}
+      onDragOver={(e) => {
+        e.preventDefault();
+      }}
       onDragLeave={() => {
-        if (dragOverRef.current) {
+        dragDepthRef.current = Math.max(0, dragDepthRef.current - 1);
+        if (dragDepthRef.current === 0 && dragOverRef.current) {
           dragOverRef.current = false;
           setDragOver(false);
         }
@@ -648,6 +685,7 @@ export function App(): ReactElement {
                 <button className="btn" onClick={onCheckUpdates}>Updates prüfen</button>
                 <button className={`btn${settingsDraft.theme === "light" ? " btn-active" : ""}`} onClick={() => {
                   const next = settingsDraft.theme === "dark" ? "light" : "dark";
+                  setSettingsDirty(true);
                   setSettingsDraft((prev) => ({ ...prev, theme: next as AppTheme }));
                   applyTheme(next as AppTheme);
                 }}>
diff --git a/tests/download-manager.test.ts b/tests/download-manager.test.ts
index 8e5e7df..169780e 100644
--- a/tests/download-manager.test.ts
+++ b/tests/download-manager.test.ts
@@ -500,7 +500,7 @@ describe("download manager", () => {
     fs.mkdirSync(pkgDir, { recursive: true });
     const existingTargetPath = path.join(pkgDir, "resume.mkv");
     fs.writeFileSync(existingTargetPath, binary.subarray(0, partialSize));
-    let seenRangeStart = -1;
+    let sawResumeRange = false;
 
     const server = http.createServer((req, res) => {
       if ((req.url || "") !== "/resume") {
@@ -512,7 +512,9 @@ describe("download manager", () => {
       const range = String(req.headers.range || "");
       const match = range.match(/bytes=(\d+)-/i);
       const start = match ? Number(match[1]) : 0;
-      seenRangeStart = start;
+      if (start === partialSize) {
+        sawResumeRange = true;
+      }
       const chunk = binary.subarray(start);
 
       if (start > 0) {
@@ -611,7 +613,7 @@ describe("download manager", () => {
       const item = manager.getSnapshot().session.items[itemId];
       expect(item?.status).toBe("completed");
       expect(item?.targetPath).toBe(existingTargetPath);
-      expect(seenRangeStart).toBe(partialSize);
+      expect(sawResumeRange).toBe(true);
       expect(fs.statSync(existingTargetPath).size).toBe(binary.length);
     } finally {
       server.close();
@@ -1945,6 +1947,105 @@ describe("download manager", () => {
     }
   });
 
+  it("handles rapid pause/resume toggles without deadlock", async () => {
+    const root = fs.mkdtempSync(path.join(os.tmpdir(), "rd-dm-"));
+    tempDirs.push(root);
+    const binary = Buffer.alloc(320 * 1024, 11);
+
+    const server = http.createServer((req, res) => {
+      if ((req.url || "") !== "/toggle-stress") {
+        res.statusCode = 404;
+        res.end("not-found");
+        return;
+      }
+      const range = String(req.headers.range || "");
+      const match = range.match(/bytes=(\d+)-/i);
+      const start = match ? Number(match[1]) : 0;
+      const chunk = binary.subarray(start);
+
+      if (start > 0) {
+        res.statusCode = 206;
+        res.setHeader("Content-Range", `bytes ${start}-${binary.length - 1}/${binary.length}`);
+      } else {
+        res.statusCode = 200;
+      }
+
+      res.setHeader("Accept-Ranges", "bytes");
+      res.setHeader("Content-Length", String(chunk.length));
+      const split = Math.max(1, Math.floor(chunk.length / 4));
+      res.write(chunk.subarray(0, split));
+      setTimeout(() => {
+        if (!res.writableEnded && !res.destroyed) {
+          res.end(chunk.subarray(split));
+        }
+      }, 260);
+    });
+
+    server.listen(0, "127.0.0.1");
+    await once(server, "listening");
+
+    const address = server.address();
+    if (!address || typeof address === "string") {
+      throw new Error("server address unavailable");
+    }
+    const directUrl = `http://127.0.0.1:${address.port}/toggle-stress`;
+
+    globalThis.fetch = async (input: RequestInfo | URL, init?: RequestInit): Promise<Response> => {
+      const url = typeof input === "string" ? input : input instanceof URL ? input.toString() : input.url;
+      if (url.includes("/unrestrict/link")) {
+        return new Response(
+          JSON.stringify({
+            download: directUrl,
+            filename: "stress.part01.rar",
+            filesize: binary.length
+          }),
+          {
+            status: 200,
+            headers: { "Content-Type": "application/json" }
+          }
+        );
+      }
+      return originalFetch(input, init);
+    };
+
+    try {
+      const manager = new DownloadManager(
+        {
+          ...defaultSettings(),
+          token: "rd-token",
+          outputDir: path.join(root, "downloads"),
+          extractDir: path.join(root, "extract"),
+          autoExtract: false,
+          maxParallel: 1
+        },
+        emptySession(),
+        createStoragePaths(path.join(root, "state"))
+      );
+
+      manager.addPackages([{ name: "toggle-stress", links: ["https://dummy/toggle-stress"] }]);
+      manager.start();
+
+      await waitFor(() => Object.values(manager.getSnapshot().session.items)[0]?.status === "downloading", 12000);
+      for (let i = 0; i < 6; i += 1) {
+        manager.togglePause();
+        await new Promise((resolve) => setTimeout(resolve, 90));
+      }
+
+      if (manager.getSnapshot().session.paused) {
+        manager.togglePause();
+      }
+
+      await waitFor(() => !manager.getSnapshot().session.running, 25000);
+      const item = Object.values(manager.getSnapshot().session.items)[0];
+      expect(item?.status).toBe("completed");
+      expect(fs.existsSync(item?.targetPath || "")).toBe(true);
+      expect(fs.statSync(item?.targetPath || "").size).toBe(binary.length);
+    } finally {
+      server.close();
+      await once(server, "close");
+    }
+  });
+
   it("keeps active downloads resumable on shutdown preparation", async () => {
     const root = fs.mkdtempSync(path.join(os.tmpdir(), "rd-dm-"));
     tempDirs.push(root);