fix: stabilize renderer state and lifecycle updates

Prevent stale history, account, diagnostics, and language updates from repainting newer state. Keep queue virtualization, panel sizing, telemetry, cancellation, and runtime timing consistent across rapid UI changes. Strengthen painted-frame and lifecycle regression coverage, and brand packaged Windows metadata with the product publisher.

tests/ui-smoke.js

@@ -35,6 +35,9 @@ const RemoteServer = require(path.join(process.cwd(), 'lib', 'remote-server'));
 const { listenOnLoopback, installLoopbackRemoteServerGuard } = require(path.join(process.cwd(), 'tests', 'support', 'ui-network-safety'));
 const updaterModule = require(path.join(process.cwd(), 'lib', 'updater'));
 const uiRemoteBindAddresses = [];
+const startupConfigPath = path.join(app.getPath('userData'), 'electron-config.json');
+fs.mkdirSync(path.dirname(startupConfigPath), { recursive: true });
+fs.writeFileSync(startupConfigPath, JSON.stringify({ globalSettings: { language: 'de' } }), 'utf8');
 installLoopbackRemoteServerGuard(RemoteServer, address => uiRemoteBindAddresses.push(address));
 let preparedUpdateMockCalls = 0;
 let launchedUpdateMockCalls = 0;
@@ -57,13 +60,28 @@ updaterModule.launchPreparedUpdate = () => {
 const initialIpcHandlers = new Map();
 const registerIpcHandler = ipcMain.handle.bind(ipcMain);
 let initialConfigReadDelayed = false;
+let startupLanguagePendingSnapshot = null;
 ipcMain.handle = (channel, listener) => {
   const registeredListener = channel === 'get-config'
     ? async (...args) => {
         const result = await listener(...args);
         if (!initialConfigReadDelayed) {
           initialConfigReadDelayed = true;
-          await new Promise(resolve => setTimeout(resolve, 4000));
+          const deadline = Date.now() + 1500;
+          let window = BrowserWindow.getAllWindows()[0];
+          while (window && !window.isVisible() && Date.now() < deadline) {
+            await new Promise(resolve => setTimeout(resolve, 25));
+            window = BrowserWindow.getAllWindows()[0];
+          }
+          startupLanguagePendingSnapshot = window
+            ? {
+                visible: window.isVisible(),
+                language: await window.webContents.executeJavaScript('document.documentElement.lang'),
+                query: await window.webContents.executeJavaScript('location.search')
+              }
+            : null;
+          const elapsed = 1500 - Math.max(0, deadline - Date.now());
+          await new Promise(resolve => setTimeout(resolve, Math.max(0, 4000 - elapsed)));
         }
         return result;
       }
@@ -132,6 +150,18 @@ setTimeout(async () => {
   const wc = win.webContents;
   const originalBounds = win.getBounds();
   const visualScreenshotDir = ${JSON.stringify(visualScreenshotDir)};
+  const rendererDiagnostics = [];
+  let rendererUnresponsiveCount = 0;
+  wc.on('console-message', (_event, level, message, line, sourceId) => {
+    if (level === 3) rendererDiagnostics.push({ type: 'console', message, line, sourceId });
+  });
+  wc.on('did-fail-load', (_event, errorCode, errorDescription, validatedURL, isMainFrame) => {
+    if (isMainFrame) rendererDiagnostics.push({ type: 'load', errorCode, errorDescription, validatedURL });
+  });
+  wc.on('render-process-gone', (_event, details) => {
+    rendererDiagnostics.push({ type: 'gone', details });
+  });
+  win.on('unresponsive', () => { rendererUnresponsiveCount++; });
 
   async function captureVisual(name) {
     if (!visualScreenshotDir) return;
@@ -159,6 +189,9 @@ setTimeout(async () => {
     check('Startup update survives pending renderer initialization', startupUpdateState === '9.9.8|false|flex|flex');
     await wc.executeJavaScript('_knownUpdateInfo = null; closeUpdateDialog(); _syncHeaderUpdateState();');
 
+    const germanStartupReady = await waitUntil(() => wc.executeJavaScript('document.documentElement.lang + "|" + document.getElementById("languageInput")?.value + "|" + [...document.querySelectorAll(".tab")].map(tab => tab.textContent.trim()).join(",")'));
+    check('Returning German profiles never expose an English frame while startup config is pending', startupLanguagePendingSnapshot !== null && (!startupLanguagePendingSnapshot.visible || startupLanguagePendingSnapshot.language === 'de') && startupLanguagePendingSnapshot.query === '?language=de' && germanStartupReady === 'de|de|Upload,Accounts,Einstellungen,Verlauf');
+    await wc.executeJavaScript('(async () => { config.globalSettings = { ...(config.globalSettings || {}), language: "en" }; await window.api.saveGlobalSettings(config.globalSettings); setUiLanguage("en"); renderSettings(); })()');
     const languageReady = await waitUntil(() => wc.executeJavaScript('Boolean(document.getElementById("languageInput"))'));
     check('Fresh profiles render in English by default', languageReady === true && await wc.executeJavaScript('document.documentElement.lang + "|" + document.getElementById("languageInput")?.value + "|" + [...document.querySelectorAll(".tab")].map(tab => tab.textContent.trim()).join(",")') === 'en|en|Upload,Accounts,Settings,History');
     await wc.executeJavaScript('document.getElementById("settings-tab").click()');
@@ -194,6 +227,20 @@ setTimeout(async () => {
     await wc.executeJavaScript('document.querySelector(".tab[data-view=upload]")?.click()');
     const liveLanguageSwitch = await wc.executeJavaScript('(() => { const input = document.getElementById("languageInput"); input.value = "de"; input.dispatchEvent(new Event("change", { bubbles: true })); const german = [...document.querySelectorAll(".tab")].map(tab => tab.textContent.trim()).join(","); input.value = "en"; input.dispatchEvent(new Event("change", { bubbles: true })); const english = [...document.querySelectorAll(".tab")].map(tab => tab.textContent.trim()).join(","); input.value = "de"; input.dispatchEvent(new Event("change", { bubbles: true })); return [german, english, document.documentElement.lang].join("|"); })()');
     check('Language changes apply immediately in both directions', liveLanguageSwitch === 'Upload,Accounts,Einstellungen,Verlauf|Upload,Accounts,Settings,History|de');
+    const localizedStableMetric = await wc.executeJavaScript(\`(async () => {
+      _sessionDoneCount = 1234;
+      updateStatusBar();
+      await new Promise(resolve => setTimeout(resolve, 360));
+      const metric = document.getElementById('uploadTelemetryCompleted');
+      const german = [metric?.textContent.trim(), metric?.getAttribute('aria-label')];
+      setUiLanguage('en');
+      const english = [metric?.textContent.trim(), metric?.getAttribute('aria-label')];
+      setUiLanguage('de');
+      _sessionDoneCount = 0;
+      updateStatusBar();
+      return { german, english };
+    })()\`);
+    check('Language changes redraw stable telemetry values with the active locale', localizedStableMetric.german.join('|') === '1.234|1.234' && localizedStableMetric.english.join('|') === '1,234|1,234');
     const germanSidebarHeadings = await wc.executeJavaScript('[...document.querySelectorAll("#upload-view, #accounts-view, #history-view")].map(view => [view.querySelector(".view-sidebar-kicker")?.textContent?.trim(), view.querySelector(".view-sidebar-title")?.textContent?.trim()].join("|"))');
     check('German sidebar hierarchy uses distinct localized kickers', germanSidebarHeadings.join('::') === 'Arbeitsbereich|Uploads::Accounts verwalten|Accounts::Archiv|Verlauf');
     const saveAfterLanguageChange = await wc.executeJavaScript('(() => { const button = document.getElementById("saveSettingsBtn"); return [button.disabled, button.classList.contains("btn-success")].join("|"); })()');
@@ -202,6 +249,28 @@ setTimeout(async () => {
     await waitUntil(() => wc.executeJavaScript('document.getElementById("saveSettingsBtn").disabled'));
     const saveAfterCommit = await wc.executeJavaScript('(() => { const button = document.getElementById("saveSettingsBtn"); return [button.disabled, button.classList.contains("btn-secondary")].join("|"); })()');
     check('Saving returns the action to its disabled gray state', saveAfterCommit === 'true|true');
+    const englishLanguageQuery = await wc.executeJavaScript(\`(async () => {
+      const input = document.getElementById('languageInput');
+      input.value = 'en';
+      input.dispatchEvent(new Event('change', { bubbles: true }));
+      await saveSettings({ feedbackText: 'Saved' });
+      return new URL(location.href).searchParams.get('language');
+    })()\`);
+    const languageReloadFinished = new Promise(resolve => wc.once('did-finish-load', resolve));
+    wc.reload();
+    await languageReloadFinished;
+    const reloadedLanguageState = await waitUntil(() => wc.executeJavaScript(\`(() => {
+      if (typeof config !== 'object' || config.globalSettings?.language !== 'en') return '';
+      return [document.documentElement.lang, location.search, [...document.querySelectorAll('.tab')].map(tab => tab.textContent.trim()).join(',')].join('|');
+    })()\`));
+    const germanLanguageQuery = await wc.executeJavaScript(\`(async () => {
+      const input = document.getElementById('languageInput');
+      input.value = 'de';
+      input.dispatchEvent(new Event('change', { bubbles: true }));
+      await saveSettings({ feedbackText: 'Gespeichert' });
+      return { query: new URL(location.href).searchParams.get('language'), active: document.documentElement.lang };
+    })()\`);
+    check('Saved language remains the startup language after a renderer reload', englishLanguageQuery === 'en' && reloadedLanguageState === 'en|?language=en|Upload,Accounts,Settings,History' && germanLanguageQuery.query === 'de' && germanLanguageQuery.active === 'de');
 
     await wc.executeJavaScript('queueJobs = []; selectedFiles = []; selectedJobIds.clear(); rebuildJobIndex(); setUploadSidebarFilter("all"); updateUploadView(); renderQueueTable(); updateStatusBar();');
     console.log('\\n=== Upload View ===');
@@ -461,6 +530,36 @@ setTimeout(async () => {
     check('Header and sidebar speed update synchronously from the same live sample', telemetryUpdate.speedPair === '2 kB/s|2 kB/s');
     const secondSynchronizedSpeed = await wc.executeJavaScript('lastUploadStats = { ...lastUploadStats, globalSpeedKbs: 1536 }; updateStatusBar(); [document.getElementById("uploadTelemetrySpeed")?.textContent, document.getElementById("uploadSpeedValue")?.textContent].join("|")');
     check('Header and sidebar speed stay synchronized across later samples', secondSynchronizedSpeed === '1.5 MB/s|1.5 MB/s');
+    const runtimeTimerRestart = await wc.executeJavaScript(\`(async () => {
+      if (statsRunTimer) clearInterval(statsRunTimer);
+      statsRunTimer = null;
+      statsStartTime = 0;
+      handleStats({ state: 'uploading', globalSpeedKbs: 1, totalBytes: 1, elapsed: 0, activeJobs: 1 });
+      const first = { start: statsStartTime, timer: statsRunTimer };
+      handleStats({ state: 'idle', globalSpeedKbs: 0, totalBytes: 1, elapsed: 1, activeJobs: 0 });
+      const idle = { start: statsStartTime, timer: statsRunTimer };
+      await new Promise(resolve => setTimeout(resolve, 2));
+      handleStats({ state: 'uploading', globalSpeedKbs: 1, totalBytes: 2, elapsed: 0, activeJobs: 1 });
+      const second = { start: statsStartTime, timer: statsRunTimer };
+      handleStats({ state: 'idle', globalSpeedKbs: 0, totalBytes: 2, elapsed: 1, activeJobs: 0 });
+      return { first, idle, second, settled: { start: statsStartTime, timer: statsRunTimer } };
+    })()\`);
+    check('Runtime telemetry starts a fresh timer for every upload batch', runtimeTimerRestart.first.start > 0 && runtimeTimerRestart.first.timer !== null && runtimeTimerRestart.idle.start === 0 && runtimeTimerRestart.idle.timer === null && runtimeTimerRestart.second.start > runtimeTimerRestart.first.start && runtimeTimerRestart.second.timer !== null && runtimeTimerRestart.settled.start === 0 && runtimeTimerRestart.settled.timer === null);
+    const failedQueueCountConsistency = await wc.executeJavaScript(\`(() => {
+      queueJobs = [
+        { id: 'failed-count-a', status: 'error', bytesTotal: 1024, bytesUploaded: 0 },
+        { id: 'failed-count-b', status: 'error', bytesTotal: 1024, bytesUploaded: 0 },
+        { id: 'failed-count-waiting', status: 'queued', bytesTotal: 1024, bytesUploaded: 0 }
+      ];
+      _sessionErrorCount = 0;
+      _queueStatsCache = null;
+      updateStatusBar();
+      return {
+        filter: document.getElementById('uploadSidebarErrorCount')?.textContent,
+        telemetry: document.getElementById('uploadTelemetryFailed')?.getAttribute('aria-label')
+      };
+    })()\`);
+    check('Failed queue jobs update the filter badge and telemetry count consistently', failedQueueCountConsistency.filter === '2' && failedQueueCountConsistency.telemetry === '2');
     await new Promise(resolve => setTimeout(resolve, 360));
     await wc.executeJavaScript('queueJobs = []; _sessionDoneCount = 0; _sessionErrorCount = 0; lastUploadStats = { ...lastUploadStats, globalSpeedKbs: 0, activeJobs: 0, state: "idle" }; updateStatusBar();');
 
@@ -953,6 +1052,64 @@ setTimeout(async () => {
     check('Account sidebar classifies disabled and credential-less accounts as action needed', accountFilterState.counters.join('|') === '4|1|2|1');
     check('Account sidebar exposes exactly one pressed filter', accountFilterState.error.pressed.join('|') === 'error' && accountFilterState.error.active.join('|') === 'error' && accountFilterState.all.pressed.join('|') === 'all' && accountFilterState.all.active.join('|') === 'all');
 
+    ipcMain.removeHandler('run-health-check');
+    ipcMain.handle('run-health-check', (_event, payload) => ({ results: (payload.hosters || []).map(item => ({ accountId: item.accountId, status: 'ok', message: 'Ready' })) }));
+    const completedAccountCheckState = await wc.executeJavaScript(\`checkSingleAccount('ui-filter-ready').then(() => ({ status: accountStatuses['ui-filter-ready']?.status, generations: accountStatusGenerations.size }))\`);
+    check('Completed account checks release their generation tokens', completedAccountCheckState.status === 'ok' && completedAccountCheckState.generations === 0);
+    restoreInitialIpcHandler('run-health-check');
+
+    let resolveStaleAccountCheck = null;
+    ipcMain.removeHandler('run-health-check');
+    ipcMain.handle('run-health-check', () => new Promise(resolve => { resolveStaleAccountCheck = resolve; }));
+    const staleAccountCheck = wc.executeJavaScript(\`(() => {
+      HOSTERS.forEach(name => { config.hosters[name] = []; });
+      config.hosters['byse.sx'] = [{ id: 'ui-stale-account-check', enabled: true, authType: 'api', apiKey: 'old-key' }];
+      accountStatuses = { 'ui-stale-account-check': { status: 'ok', message: 'Old credentials ready' } };
+      healthCheckRunning = false;
+      renderAccounts();
+      return checkSingleAccount('ui-stale-account-check');
+    })()\`);
+    await waitUntil(() => resolveStaleAccountCheck);
+    await wc.executeJavaScript(\`(() => {
+      const candidateHosters = structuredClone(config.hosters);
+      candidateHosters['byse.sx'][0].apiKey = 'new-key';
+      _applyCommittedAccount(
+        { accountId: 'ui-stale-account-check', candidateHosters, isEdit: true },
+        { status: 'ok', message: 'New credentials ready' }
+      );
+    })()\`);
+    resolveStaleAccountCheck({ results: [{ accountId: 'ui-stale-account-check', status: 'error', message: 'Old credential check failed' }] });
+    await staleAccountCheck;
+    const staleAccountCheckState = await wc.executeJavaScript(\`(() => {
+      const status = accountStatuses['ui-stale-account-check'];
+      const card = document.querySelector('[data-account-id="ui-stale-account-check"]');
+      return { status: status?.status, message: status?.message, card: card?.querySelector('.account-status')?.textContent.trim() };
+    })()\`);
+    check('A late account check cannot overwrite newly committed credentials', staleAccountCheckState.status === 'ok' && staleAccountCheckState.message === 'New credentials ready' && staleAccountCheckState.card === 'Bereit');
+    restoreInitialIpcHandler('run-health-check');
+
+    let resolveImportedAccountCheck = null;
+    ipcMain.removeHandler('run-health-check');
+    ipcMain.handle('run-health-check', () => new Promise(resolve => { resolveImportedAccountCheck = resolve; }));
+    const importedAccountCheck = wc.executeJavaScript(\`(() => {
+      healthCheckRunning = false;
+      return checkSingleAccount('ui-stale-account-check');
+    })()\`);
+    await waitUntil(() => resolveImportedAccountCheck);
+    await wc.executeJavaScript(\`(() => {
+      const imported = structuredClone(config);
+      imported.hosters['byse.sx'][0].apiKey = 'imported-key';
+      applyImportedConfig(imported, 'Importiert');
+    })()\`);
+    resolveImportedAccountCheck({ results: [{ accountId: 'ui-stale-account-check', status: 'error', message: 'Pre-import credentials failed' }] });
+    await importedAccountCheck;
+    const importedAccountCheckState = await wc.executeJavaScript(\`(() => {
+      const status = accountStatuses['ui-stale-account-check'];
+      return { status: status?.status, message: status?.message || '', generations: accountStatusGenerations.size, apiKey: config.hosters['byse.sx'][0].apiKey };
+    })()\`);
+    check('A backup import invalidates account checks started with older credentials', importedAccountCheckState.status === 'unchecked' && importedAccountCheckState.message === '' && importedAccountCheckState.generations === 0 && importedAccountCheckState.apiKey === 'imported-key');
+    restoreInitialIpcHandler('run-health-check');
+
     console.log('\\n=== Settings View ===');
 
     await wc.executeJavaScript('document.querySelector(".tab[data-view=\\'settings\\']").click()');
@@ -1047,6 +1204,21 @@ setTimeout(async () => {
     await wc.executeJavaScript('document.querySelector("[data-settings-page=\\'diagnose\\']")?.click()');
     const diagnoseSettingsSpacing = await wc.executeJavaScript('(() => { const grid = document.querySelector("[data-subpage=diagnose] .settings-grid-mini")?.getBoundingClientRect(); const port = document.getElementById("diagPortInput")?.closest(".settings-row")?.getBoundingClientRect(); return grid && port ? Math.round(port.top - grid.bottom) : -1; })()');
     check('Diagnose settings keep space before Port', diagnoseSettingsSpacing >= 8);
+
+    let resolveStaleDiagnosticsSettings = null;
+    ipcMain.removeHandler('diagnostics:get-settings');
+    ipcMain.handle('diagnostics:get-settings', () => new Promise(resolve => { resolveStaleDiagnosticsSettings = resolve; }));
+    await wc.executeJavaScript('renderSettings()');
+    await waitUntil(() => resolveStaleDiagnosticsSettings);
+    await wc.executeJavaScript('document.querySelector("[data-settings-page=diagnose]")?.click(); (() => { const input = document.getElementById("diagPortInput"); input.value = "9222"; input.dispatchEvent(new Event("input", { bubbles: true })); })()');
+    resolveStaleDiagnosticsSettings({ enabled: true, port: 9110, bindMode: 'network', publicHost: 'diagnostics.example.test', allowlist: ['100.64.0.0/10'] });
+    await new Promise(resolve => setTimeout(resolve, 80));
+    const staleDiagnosticsState = await wc.executeJavaScript('(() => ({ port: document.getElementById("diagPortInput")?.value, enabled: document.getElementById("diagEnabledInput")?.checked, bindMode: document.getElementById("diagBindModeInput")?.value, publicHost: document.getElementById("diagPublicHostInput")?.value, allowlist: document.getElementById("diagAllowlistInput")?.value }))()');
+    check('A late diagnostics response preserves the edited field and fills every untouched field', staleDiagnosticsState.port === '9222' && staleDiagnosticsState.enabled === true && staleDiagnosticsState.bindMode === 'network' && staleDiagnosticsState.publicHost === 'diagnostics.example.test' && staleDiagnosticsState.allowlist === '100.64.0.0/10');
+    restoreInitialIpcHandler('diagnostics:get-settings');
+    await wc.executeJavaScript('renderSettings(); document.querySelector("[data-settings-page=diagnose]")?.click()');
+    await new Promise(resolve => setTimeout(resolve, 80));
+
     const diagnosticsDirtyTracking = await wc.executeJavaScript('(async () => { const original = await window.api.diagnosticsGetSettings(); const input = document.getElementById("diagPublicHostInput"); establishSettingsBaseline(); input.value = "ui-diagnostics-save.invalid"; input.dispatchEvent(new Event("input", { bubbles: true })); const button = document.getElementById("saveSettingsBtn"); const enabled = button.disabled === false && button.classList.contains("btn-success"); if (enabled) await saveSettings({ feedbackText: "Gespeichert" }); const persisted = await window.api.diagnosticsGetSettings(); await saveDiagnosticsSettingsTracked(original); input.value = original.publicHost || ""; establishSettingsBaseline(); return { enabled, persisted: persisted.publicHost }; })()');
     check('Diagnostics changes enable Save and persist with the full settings form', diagnosticsDirtyTracking.enabled === true && diagnosticsDirtyTracking.persisted === 'ui-diagnostics-save.invalid');
 
@@ -1506,6 +1678,48 @@ setTimeout(async () => {
     const historyActive = await wc.executeJavaScript('document.getElementById("history-view")?.classList.contains("active")');
     check('History tab active', historyActive);
 
+    const historyRaceResolvers = [];
+    ipcMain.removeHandler('get-history');
+    ipcMain.handle('get-history', () => new Promise(resolve => { historyRaceResolvers.push(resolve); }));
+    const staleHistoryLoad = wc.executeJavaScript('loadHistory()');
+    await waitUntil(() => historyRaceResolvers.length === 1);
+    const latestHistoryLoad = wc.executeJavaScript('loadHistory()');
+    await waitUntil(() => historyRaceResolvers.length === 2);
+    historyRaceResolvers[1]([{ timestamp: '2026-08-10T10:00:01.000Z', files: [{ name: 'latest-history.bin', results: [{ status: 'done', hoster: 'voe.sx', download_url: 'https://example.invalid/latest' }] }] }]);
+    await latestHistoryLoad;
+    historyRaceResolvers[0]([{ timestamp: '2026-08-10T10:00:00.000Z', files: [{ name: 'stale-history.bin', results: [{ status: 'done', hoster: 'voe.sx', download_url: 'https://example.invalid/stale' }] }] }]);
+    await staleHistoryLoad;
+    const historyRaceResult = await wc.executeJavaScript('[...document.querySelectorAll("#historyBody .history-row .col-filename")].map(cell => cell.textContent.trim()).join("|")');
+    check('A late stale history response cannot overwrite the latest rendered history', historyRaceResult === 'latest-history.bin');
+    ipcMain.removeHandler('get-history');
+    ipcMain.handle('get-history', () => historyFixture);
+    await wc.executeJavaScript('loadHistory()');
+
+    const historyFixtureBeforeLifetimeCheck = historyFixture;
+    historyFixture = [{
+      timestamp: '2026-08-10T10:05:00.000Z',
+      files: [{ name: 'lifetime.bin', results: [{ status: 'done', hoster: 'voe.sx', download_url: 'https://example.invalid/lifetime' }] }]
+    }];
+    await wc.executeJavaScript(\`(() => {
+      HOSTERS.forEach(name => { config.hosters[name] = []; });
+      config.hosters['voe.sx'] = [{ id: 'ui-lifetime-account', enabled: true, authType: 'login', username: 'lifetime@example.invalid', password: 'fictional-password' }];
+      accountStatuses = { 'ui-lifetime-account': { status: 'ok', message: 'Bereit' } };
+      window._historyForStats = [];
+      _invalidateHosterLifetimeCache();
+      renderAccounts();
+      window.__uiLifetimeGroup = document.querySelector('[data-hoster-group="voe.sx"]');
+    })()\`);
+    await wc.executeJavaScript('loadHistory()');
+    const lifetimeRefreshState = await wc.executeJavaScript(\`(() => {
+      const group = document.querySelector('[data-hoster-group="voe.sx"]');
+      const meta = group?.querySelector('[data-hoster-lifetime="voe.sx"]');
+      return { sameGroup: group === window.__uiLifetimeGroup, visible: Boolean(meta && !meta.hidden), text: meta?.textContent.trim() || '' };
+    })()\`);
+    check('Loaded history refreshes hoster lifetime success without replacing the account group', lifetimeRefreshState.sameGroup && lifetimeRefreshState.visible && lifetimeRefreshState.text === '100% ok (1)');
+    historyFixture = historyFixtureBeforeLifetimeCheck;
+    await wc.executeJavaScript('loadHistory()');
+    await wc.executeJavaScript('HOSTERS.forEach(name => { config.hosters[name] = []; }); accountStatuses = {}; renderAccounts()');
+
     const historyWorkspaceLayout = await wc.executeJavaScript('(() => { const view = document.getElementById("history-view"); const sidebar = view?.querySelector(":scope > .view-sidebar"); const main = view?.querySelector(":scope > .view-main"); if (!sidebar || !main) return false; const sidebarRect = sidebar.getBoundingClientRect(); const mainRect = main.getBoundingClientRect(); return sidebarRect.width > 0 && mainRect.width > 0 && sidebarRect.right <= mainRect.left; })()');
     check('History view separates sidebar and main workspace', historyWorkspaceLayout === true);
 
@@ -1721,7 +1935,70 @@ setTimeout(async () => {
     })()\`);
     check('Unavailable recent, queue, and history actions are disabled', emptyActionState === 'true|true|true|true|true');
 
+    const recentLocaleState = await wc.executeJavaScript(\`(() => {
+      const timestamp = Date.UTC(2026, 7, 10, 13, 14, 15);
+      setUiLanguage('de');
+      sessionFilesData = [{ date: formatDateTime(timestamp).text, dateTs: timestamp, filename: 'locale.bin', host: 'voe.sx', link: 'https://example.invalid/locale', isError: false, order: 1 }];
+      _recentDataVersion++;
+      renderRecentUploadsPanel();
+      const german = document.querySelector('#recentFilesBody .recent-file-row td')?.textContent.trim();
+      setUiLanguage('en');
+      const english = document.querySelector('#recentFilesBody .recent-file-row td')?.textContent.trim();
+      const expectedEnglish = formatDateTime(timestamp).text;
+      setUiLanguage('de');
+      sessionFilesData = [];
+      _recentDataVersion++;
+      renderRecentUploadsPanel();
+      return { german, english, expectedEnglish };
+    })()\`);
+    check('Recent upload timestamps immediately follow the selected interface language', recentLocaleState.german !== recentLocaleState.english && recentLocaleState.english === recentLocaleState.expectedEnglish);
+
+    const recentCapScrollState = await wc.executeJavaScript(\`(() => {
+      document.querySelector('.tab[data-view="upload"]')?.click();
+      queueJobs = [{ id: 'ui-recent-cap', file: 'C:/ui/recent-cap.bin', fileName: 'recent-cap.bin', hoster: 'byse.sx', status: 'queued', bytesUploaded: 0, bytesTotal: 100, progress: 0 }];
+      rebuildJobIndex();
+      updateUploadView();
+      renderQueueTable();
+      recentSortState.key = 'date';
+      recentSortState.direction = 'desc';
+      sessionFilesData = Array.from({ length: SESSION_FILES_CAP }, (_, index) => ({
+        date: String(index),
+        dateTs: index,
+        filename: 'cap-' + index + '.bin',
+        host: 'byse.sx',
+        link: 'https://example.invalid/cap-' + index,
+        isError: false,
+        order: index
+      }));
+      _recentDataVersion++;
+      renderRecentUploadsPanel();
+      const wrap = document.querySelector('.recent-files-table-wrap');
+      wrap.scrollTop = 560;
+      const before = wrap.scrollTop;
+      sessionFilesData = sessionFilesData.slice(1);
+      sessionFilesData.push({ date: 'new', dateTs: SESSION_FILES_CAP + 1, filename: 'cap-new.bin', host: 'byse.sx', link: 'https://example.invalid/cap-new', isError: false, order: SESSION_FILES_CAP + 1 });
+      _recentPendingAppends = 1;
+      _recentDataVersion++;
+      renderRecentUploadsPanel();
+      const after = wrap.scrollTop;
+      sessionFilesData = [];
+      _recentPendingAppends = 0;
+      _recentDataVersion++;
+      renderRecentUploadsPanel();
+      queueJobs = [];
+      rebuildJobIndex();
+      updateUploadView();
+      renderQueueTable();
+      return { before, after, delta: after - before };
+    })()\`);
+    if (!(recentCapScrollState.before > 0 && Math.abs(recentCapScrollState.delta - 28) <= 1)) console.log('Recent cap scroll state: ' + JSON.stringify(recentCapScrollState));
+    check('A capped recent-upload list preserves the visible rows when a new item arrives', recentCapScrollState.before > 0 && Math.abs(recentCapScrollState.delta - 28) <= 1);
+
     const keyboardInteractionContract = await wc.executeJavaScript(\`(() => {
+      HOSTERS.forEach(name => { config.hosters[name] = []; });
+      config.hosters['byse.sx'] = [{ id: 'ui-keyboard-account', enabled: true, authType: 'api', apiKey: 'keyboard-key' }];
+      accountStatuses = { 'ui-keyboard-account': { status: 'ok', message: 'Bereit' } };
+      renderAccounts();
       queueJobs = [{ id: 'ui-keyboard-row', file: 'C:/ui/keyboard.bin', fileName: 'keyboard.bin', hoster: 'byse.sx', status: 'queued', bytesUploaded: 0, bytesTotal: 100, progress: 0 }];
       selectedJobIds.clear();
       rebuildJobIndex();
@@ -1771,6 +2048,240 @@ setTimeout(async () => {
     ].join('|'))()\`);
     check('Hoster, job log, delete-account, and shutdown surfaces expose dialog semantics', modalSemantics === 'dialog|dialog|dialog|dialog');
 
+    const rapidViewStability = await wc.executeJavaScript(\`(async () => {
+      const sequence = ['upload', 'accounts', 'settings', 'history', 'settings', 'accounts', 'upload', 'history', 'upload', 'accounts', 'history', 'settings'];
+      const samples = [];
+      for (const target of sequence) {
+        document.querySelector('.tab[data-view="' + target + '"]')?.click();
+        await new Promise(resolve => requestAnimationFrame(() => requestAnimationFrame(resolve)));
+        const activeViews = [...document.querySelectorAll('.view.active')];
+        const activeTabs = [...document.querySelectorAll('.tab.active')];
+        const viewRect = activeViews[0]?.getBoundingClientRect();
+        const speedRect = document.getElementById('uploadSpeedSparkline')?.getBoundingClientRect();
+        const indicatorRect = document.querySelector('.tab-indicator')?.getBoundingClientRect();
+        samples.push({
+          target,
+          activeViews: activeViews.length,
+          activeTabs: activeTabs.length,
+          activeView: activeViews[0]?.id,
+          activeTab: activeTabs[0]?.dataset.view,
+          viewVisible: Boolean(viewRect && viewRect.width > 0 && viewRect.height > 0),
+          speedVisible: Boolean(speedRect && speedRect.width > 0 && speedRect.height > 0),
+          indicatorVisible: Boolean(indicatorRect && indicatorRect.width > 0 && indicatorRect.height > 0),
+          horizontalOverflow: document.documentElement.scrollWidth > document.documentElement.clientWidth + 1
+        });
+      }
+      document.querySelector('.tab[data-view="upload"]')?.click();
+      return samples;
+    })()\`);
+    const invalidViewFrames = rapidViewStability.filter(sample => sample.activeViews !== 1 || sample.activeTabs !== 1 || sample.activeView !== sample.target + '-view' || sample.activeTab !== sample.target || !sample.viewVisible || !sample.speedVisible || !sample.indicatorVisible || sample.horizontalOverflow);
+    check('Rapid main-view switches never paint a blank, duplicate, or overflowing active view', rapidViewStability.length === 12 && invalidViewFrames.length === 0);
+
+    const languageFrameStability = await wc.executeJavaScript(\`(async () => {
+      _sessionDoneCount = 1234;
+      const languages = ['en', 'de', 'en', 'de', 'en', 'de', 'en', 'de', 'en', 'de', 'en', 'de'];
+      const samples = [];
+      for (const language of languages) {
+        setUiLanguage(language);
+        await new Promise(resolve => requestAnimationFrame(() => requestAnimationFrame(resolve)));
+        const metric = document.getElementById('uploadTelemetryCompleted');
+        samples.push({
+          requested: language,
+          active: document.documentElement.lang,
+          tabs: [...document.querySelectorAll('.tab')].map(tab => tab.textContent.trim()).join('|'),
+          settingsTitle: document.querySelector('[data-subpage="allgemein"] .settings-page-header h3')?.textContent.trim(),
+          uploadKicker: document.querySelector('#upload-view .view-sidebar-kicker')?.textContent.trim(),
+          metricValues: [...(metric?.querySelectorAll(':scope > span') || [])].map(span => span.textContent.trim()),
+          metricLabel: metric?.getAttribute('aria-label')
+        });
+      }
+      _sessionDoneCount = 0;
+      updateStatusBar();
+      return samples;
+    })()\`);
+    const invalidLanguageFrames = languageFrameStability.filter(sample => sample.requested === 'en'
+      ? sample.active !== 'en' || sample.tabs !== 'Upload|Accounts|Settings|History' || sample.settingsTitle !== 'General' || sample.uploadKicker !== 'Workspace' || sample.metricLabel !== '1,234' || sample.metricValues.length === 0 || sample.metricValues.some(value => value !== '0' && value !== '1,234')
+      : sample.active !== 'de' || sample.tabs !== 'Upload|Accounts|Einstellungen|Verlauf' || sample.settingsTitle !== 'Allgemein' || sample.uploadKicker !== 'Arbeitsbereich' || sample.metricLabel !== '1.234' || sample.metricValues.length === 0 || sample.metricValues.some(value => value !== '0' && value !== '1.234'));
+    if (invalidLanguageFrames.length) console.log('Invalid language frames: ' + JSON.stringify(invalidLanguageFrames));
+    check('Rapid language switches expose only complete, locale-consistent painted frames', languageFrameStability.length === 12 && invalidLanguageFrames.length === 0);
+
+    const rollingMetricStability = await wc.executeJavaScript(\`(async () => {
+      setUiLanguage('de');
+      await new Promise(resolve => setTimeout(resolve, 360));
+      const metric = document.getElementById('uploadTelemetryCompleted');
+      const initialRect = metric.getBoundingClientRect();
+      const frames = [];
+      for (let value = 1000; value <= 1020; value++) {
+        _sessionDoneCount = value;
+        updateStatusBar();
+        await new Promise(resolve => requestAnimationFrame(() => requestAnimationFrame(resolve)));
+        const rect = metric.getBoundingClientRect();
+        frames.push({
+          text: metric.textContent.trim(),
+          label: metric.getAttribute('aria-label'),
+          childCount: metric.querySelectorAll(':scope > span').length,
+          width: rect.width,
+          height: rect.height
+        });
+      }
+      await new Promise(resolve => setTimeout(resolve, 360));
+      const settled = { text: metric.textContent.trim(), label: metric.getAttribute('aria-label'), direction: metric.dataset.direction };
+      _sessionDoneCount = 0;
+      updateStatusBar();
+      return { initialRect: { width: initialRect.width, height: initialRect.height }, frames, settled };
+    })()\`);
+    const invalidRollingFrames = rollingMetricStability.frames.filter(frame => !frame.text || !frame.label || frame.childCount < 1 || frame.childCount > 2 || Math.abs(frame.width - rollingMetricStability.initialRect.width) > 0.5 || Math.abs(frame.height - rollingMetricStability.initialRect.height) > 0.5);
+    check('Rapid telemetry updates never expose an empty value or shift the metric layout', rollingMetricStability.frames.length === 21 && invalidRollingFrames.length === 0 && rollingMetricStability.settled.text === '1.020' && rollingMetricStability.settled.label === '1.020' && rollingMetricStability.settled.direction === 'none');
+
+    const virtualQueueStability = await wc.executeJavaScript(\`(async () => {
+      const total = 1200;
+      queueJobs = Array.from({ length: total }, (_, index) => ({
+        id: 'ui-stress-' + index,
+        file: 'C:/ui/stress-' + index + '.bin',
+        fileName: 'stress-' + String(index).padStart(4, '0') + '.bin',
+        hoster: 'byse.sx',
+        status: 'uploading',
+        bytesUploaded: 100,
+        bytesTotal: 1000,
+        speedKbs: 64,
+        elapsed: 1,
+        remaining: 9,
+        progress: .1
+      }));
+      rebuildJobIndex();
+      queueSortState.key = 'filename';
+      queueSortState.direction = 'asc';
+      setUploadSidebarFilter('all');
+      updateUploadView();
+      renderQueueTable();
+      const container = document.getElementById('queueContainer');
+      container.scrollTop = 5600;
+      container.dispatchEvent(new Event('scroll'));
+      await new Promise(resolve => requestAnimationFrame(() => requestAnimationFrame(resolve)));
+      const tbody = document.getElementById('queueBody');
+      const originalRows = [...tbody.querySelectorAll('.queue-row')];
+      const originalIds = originalRows.map(row => row.dataset.jobId);
+      const originalScrollTop = container.scrollTop;
+      let childMutations = 0;
+      let blankFrames = 0;
+      let identityChanges = 0;
+      const observer = new MutationObserver(records => {
+        childMutations += records.filter(record => record.type === 'childList').length;
+      });
+      observer.observe(tbody, { childList: true });
+      for (let frame = 0; frame < 36; frame++) {
+        for (const id of originalIds) {
+          const job = _jobIndexById.get(id);
+          if (!job) continue;
+          job.progress = Math.min(1, job.progress + .0005);
+          job.bytesUploaded = Math.round(job.progress * job.bytesTotal);
+        }
+        renderQueueTable();
+        await new Promise(resolve => requestAnimationFrame(() => requestAnimationFrame(resolve)));
+        const rows = [...tbody.querySelectorAll('.queue-row')];
+        if (!rows.length || rows.some(row => !row.querySelector('.col-filename')?.textContent.trim())) blankFrames++;
+        if (rows.length !== originalRows.length || rows.some((row, index) => row !== originalRows[index])) identityChanges++;
+      }
+      observer.disconnect();
+      const scrollDrift = Math.abs(container.scrollTop - originalScrollTop);
+      const activeIds = new Set(originalIds);
+      queueJobs.forEach(job => { job.status = activeIds.has(job.id) ? 'uploading' : 'done'; });
+      setUploadSidebarFilter('active');
+      updateUploadView();
+      renderQueueTable();
+      const result = {
+        total,
+        rendered: originalRows.length,
+        childMutations,
+        blankFrames,
+        identityChanges,
+        scrollDrift,
+        filteredRows: tbody.querySelectorAll('.queue-row').length,
+        filteredHasVirtualSpacer: Boolean(tbody.querySelector('.virtual-spacer'))
+      };
+      setUploadSidebarFilter('all');
+      queueJobs = [];
+      rebuildJobIndex();
+      renderQueueTable();
+      updateUploadView();
+      updateStatusBar();
+      return result;
+    })()\`);
+    check('High-frequency updates keep virtual queue rows mounted without blank frames or scroll jumps', virtualQueueStability.total === 1200 && virtualQueueStability.rendered > 0 && virtualQueueStability.rendered < 1200 && virtualQueueStability.childMutations === 0 && virtualQueueStability.blankFrames === 0 && virtualQueueStability.identityChanges === 0 && virtualQueueStability.scrollDrift <= 1);
+    check('Switching from a virtual queue to a small filtered result removes virtual spacers', virtualQueueStability.filteredRows === virtualQueueStability.rendered && virtualQueueStability.filteredHasVirtualSpacer === false);
+
+    win.setSize(1100, 900);
+    await new Promise(resolve => setTimeout(resolve, 100));
+    await wc.executeJavaScript('document.querySelector(".tab[data-view=upload]")?.click(); queueJobs = [{ id: "ui-panel-resize", file: "C:/ui/panel-resize.bin", fileName: "panel-resize.bin", hoster: "byse.sx", status: "queued", bytesUploaded: 0, bytesTotal: 100, progress: 0 }]; rebuildJobIndex(); updateUploadView(); renderQueueTable(); document.getElementById("recentFilesPanel").style.flex = "0 0 600px"');
+    win.setSize(1100, 550);
+    await new Promise(resolve => setTimeout(resolve, 140));
+    const recentPanelResizeState = await wc.executeJavaScript('(() => { const panel = document.getElementById("recentFilesPanel"); const queue = document.getElementById("queueContainer"); return { panelHeight: panel.getBoundingClientRect().height, queueHeight: queue.getBoundingClientRect().height, viewportHeight: window.innerHeight }; })()');
+    if (!(recentPanelResizeState.panelHeight <= recentPanelResizeState.viewportHeight * 0.7 + 1 && recentPanelResizeState.queueHeight >= 120)) console.log('Recent panel resize state: ' + JSON.stringify(recentPanelResizeState));
+    check('A manually enlarged recent panel is clamped after a height-only window shrink', recentPanelResizeState.panelHeight <= recentPanelResizeState.viewportHeight * 0.7 + 1 && recentPanelResizeState.queueHeight >= 120);
+    win.setSize(1100, 900);
+    await new Promise(resolve => setTimeout(resolve, 140));
+    const initialHiddenResizeState = await wc.executeJavaScript('(() => { document.querySelector(".tab[data-view=upload]")?.click(); const panel = document.getElementById("recentFilesPanel"); panel.style.flex = "0 0 600px"; clampRecentPanelHeight(); const queue = document.getElementById("queueContainer"); return { basis: parseFloat(panel.style.flexBasis), panelHeight: panel.getBoundingClientRect().height, queueHeight: queue.getBoundingClientRect().height }; })()');
+    await wc.executeJavaScript('document.querySelector(".tab[data-view=settings]")?.click()');
+    win.setSize(1100, 550);
+    await new Promise(resolve => setTimeout(resolve, 140));
+    const hiddenRecentPanelState = await wc.executeJavaScript('(() => { const panel = document.getElementById("recentFilesPanel"); return { basis: parseFloat(panel.style.flexBasis), panelHeight: panel.getBoundingClientRect().height }; })()');
+    await wc.executeJavaScript('document.querySelector(".tab[data-view=upload]")?.click()');
+    await new Promise(resolve => setTimeout(resolve, 140));
+    const restoredRecentPanelState = await wc.executeJavaScript('(() => { const panel = document.getElementById("recentFilesPanel"); const queue = document.getElementById("queueContainer"); return { basis: parseFloat(panel.style.flexBasis), panelHeight: panel.getBoundingClientRect().height, queueHeight: queue.getBoundingClientRect().height, viewportHeight: window.innerHeight }; })()');
+    const hiddenResizePreserved = hiddenRecentPanelState.panelHeight === 0 && Math.abs(hiddenRecentPanelState.basis - initialHiddenResizeState.basis) <= 0.5;
+    const hiddenResizeRestored = restoredRecentPanelState.basis < initialHiddenResizeState.basis && restoredRecentPanelState.queueHeight >= 120 && restoredRecentPanelState.panelHeight <= restoredRecentPanelState.viewportHeight * 0.7 + 1;
+    if (!(hiddenResizePreserved && hiddenResizeRestored)) console.log('Hidden recent panel resize state: ' + JSON.stringify({ initialHiddenResizeState, hiddenRecentPanelState, restoredRecentPanelState }));
+    check('Resizing another tab preserves the requested recent height while hidden', hiddenResizePreserved);
+    check('Returning to Upload reclamps the recent panel and restores queue space', hiddenResizeRestored);
+    await wc.executeJavaScript('document.getElementById("recentFilesPanel").style.flex = ""; queueJobs = []; rebuildJobIndex(); updateUploadView(); renderQueueTable()');
+
+    const resizeStability = [];
+    for (let cycle = 0; cycle < 8; cycle++) {
+      const width = cycle % 2 === 0 ? 800 : 1100;
+      const height = cycle % 2 === 0 ? 550 : 750;
+      win.setSize(width, height);
+      await new Promise(resolve => setTimeout(resolve, 80));
+      resizeStability.push(await wc.executeJavaScript(\`(async () => {
+        const samples = [];
+        for (const target of ['upload', 'accounts', 'settings', 'history']) {
+          document.querySelector('.tab[data-view="' + target + '"]')?.click();
+          await new Promise(resolve => requestAnimationFrame(() => requestAnimationFrame(resolve)));
+          const active = document.querySelector('.view.active');
+          const rect = active?.getBoundingClientRect();
+          const settingsHeader = target === 'settings' ? document.querySelector('.settings-header') : null;
+          const settingsHeaderRect = settingsHeader?.getBoundingClientRect();
+          const settingsHeaderStyle = settingsHeader ? getComputedStyle(settingsHeader) : null;
+          const settingsSaveButton = target === 'settings' ? document.getElementById('saveSettingsBtn') : null;
+          const settingsSaveButtonStyle = settingsSaveButton ? getComputedStyle(settingsSaveButton) : null;
+          samples.push({
+            target,
+            visible: Boolean(rect && rect.width > 0 && rect.height > 0),
+            contained: Boolean(active && active.scrollWidth <= active.clientWidth + 1),
+            activeViews: document.querySelectorAll('.view.active').length,
+            settingsHeaderHeight: settingsHeaderRect?.height || null,
+            settingsHeaderMetrics: settingsHeader ? {
+              innerWidth: window.innerWidth,
+              minHeight: settingsHeaderStyle.minHeight,
+              saveHeight: settingsSaveButton.getBoundingClientRect().height,
+              saveMinHeight: settingsSaveButtonStyle.minHeight
+            } : null
+          });
+        }
+        return {
+          samples,
+          documentContained: document.documentElement.scrollWidth <= document.documentElement.clientWidth + 1
+        };
+      })()\`));
+    }
+    win.setBounds(originalBounds);
+    await new Promise(resolve => setTimeout(resolve, 150));
+    await wc.executeJavaScript('document.querySelector(".tab[data-view=upload]")?.click()');
+    const invalidResizeFrames = resizeStability.filter(cycle => !cycle.documentContained || cycle.samples.some(sample => !sample.visible || !sample.contained || sample.activeViews !== 1 || (sample.target === 'settings' && (sample.settingsHeaderHeight <= 0 || sample.settingsHeaderHeight > (sample.settingsHeaderMetrics.innerWidth <= 839 ? 58 : 64)))));
+    if (invalidResizeFrames.length) console.log('Invalid resize frames: ' + JSON.stringify(invalidResizeFrames));
+    check('Repeated minimum and standard resizes keep every view painted and contained', resizeStability.length === 8 && invalidResizeFrames.length === 0);
+    if (rendererDiagnostics.length) console.log('Renderer diagnostics: ' + JSON.stringify(rendererDiagnostics));
+    check('Dynamic rendering emits no renderer errors, failed loads, crashes, or unresponsive events', rendererDiagnostics.length === 0 && rendererUnresponsiveCount === 0);
+
     const updateHidden = await wc.executeJavaScript('document.getElementById("updateBanner")?.style.display');
     check('Update banner hidden', updateHidden === 'none');