fix: log/tasks rendering

webui/backend/tests/golden/test_ui_smoke_golden.py

@@ -246,6 +246,8 @@ class UiSmokeGoldenTest(unittest.TestCase):
         self.assertIn('async function loadTasksForSettings()', app_js)
         self.assertIn('async function loadLogsAndTasksForSettings()', app_js)
         self.assertIn('function scheduleSettingsLogsPolling()', app_js)
+        self.assertIn('lastHistoryRenderKey: ""', app_js)
+        self.assertIn('lastTasksRenderKey: ""', app_js)
         self.assertIn('function openZipDownloadModal(selectedItems)', app_js)
         self.assertIn('function openSingleFileDownloadModal(selectedItem)', app_js)
         self.assertIn('function markZipDownloadReady(fileName)', app_js)
@@ -300,6 +302,14 @@ class UiSmokeGoldenTest(unittest.TestCase):
         self.assertIn('return "Multi-item ZIP";', app_js)
         self.assertIn('details.push(`Current: ${task.current_item}`);', app_js)
         self.assertIn('details.push(`${task.done_items}/${task.total_items} items`);', app_js)
+        self.assertIn('if (settingsState.lastHistoryRenderKey === renderKey) {', app_js)
+        self.assertIn('if (settingsState.lastTasksRenderKey === renderKey) {', app_js)
+        self.assertIn('const scrollTop = elements.logsList.scrollTop;', app_js)
+        self.assertIn('const scrollTop = elements.tasksList.scrollTop;', app_js)
+        self.assertIn('elements.logsList.scrollTop = scrollTop;', app_js)
+        self.assertIn('elements.tasksList.scrollTop = scrollTop;', app_js)
+        self.assertIn('if (!settingsState.tasksLoaded) {', app_js)
+        self.assertIn('if (!settingsState.logsLoaded) {', app_js)
         self.assertIn('downloadModal.logsButton.onclick = () => {', app_js)
         self.assertIn('openSettings("logs");', app_js)
         self.assertIn('function applyContextMenuSelection()', app_js)

webui/html/app.js

@@ -103,6 +103,8 @@ let settingsState = {
   logsLoaded: false,
   tasksLoaded: false,
   logsPollTimer: null,
+  lastHistoryRenderKey: "",
+  lastTasksRenderKey: "",
   showThumbnails: false,
   preferredStartupPathLeft: null,
   preferredStartupPathRight: null,
@@ -3804,12 +3806,18 @@ function formatTaskLine(task) {
 
 function renderHistoryItems(items) {
   const elements = settingsElements();
+  const renderKey = JSON.stringify(Array.isArray(items) ? items : []);
+  if (settingsState.lastHistoryRenderKey === renderKey) {
+    return;
+  }
+  const scrollTop = elements.logsList.scrollTop;
   elements.logsList.innerHTML = "";
   if (!Array.isArray(items) || items.length === 0) {
     const empty = document.createElement("div");
     empty.className = "popup-meta";
     empty.textContent = "No history entries yet.";
     elements.logsList.append(empty);
+    settingsState.lastHistoryRenderKey = renderKey;
     return;
   }
   for (const item of items) {
@@ -3834,16 +3842,24 @@ function renderHistoryItems(items) {
     }
     elements.logsList.append(row);
   }
+  settingsState.lastHistoryRenderKey = renderKey;
+  elements.logsList.scrollTop = scrollTop;
 }
 
 function renderTaskItems(items) {
   const elements = settingsElements();
+  const renderKey = JSON.stringify(Array.isArray(items) ? items : []);
+  if (settingsState.lastTasksRenderKey === renderKey) {
+    return;
+  }
+  const scrollTop = elements.tasksList.scrollTop;
   elements.tasksList.innerHTML = "";
   if (!Array.isArray(items) || items.length === 0) {
     const empty = document.createElement("div");
     empty.className = "popup-meta";
     empty.textContent = "No tasks yet.";
     elements.tasksList.append(empty);
+    settingsState.lastTasksRenderKey = renderKey;
     return;
   }
   for (const task of items) {
@@ -3868,6 +3884,8 @@ function renderTaskItems(items) {
     }
     elements.tasksList.append(row);
   }
+  settingsState.lastTasksRenderKey = renderKey;
+  elements.tasksList.scrollTop = scrollTop;
 }
 
 async function loadHistoryForSettings() {
@@ -3885,8 +3903,12 @@ async function loadTasksForSettings() {
 async function loadLogsAndTasksForSettings() {
   const elements = settingsElements();
   elements.logsError.textContent = "";
+  if (!settingsState.tasksLoaded) {
     elements.tasksList.innerHTML = '<div class="popup-meta">Loading...</div>';
+  }
+  if (!settingsState.logsLoaded) {
     elements.logsList.innerHTML = '<div class="popup-meta">Loading...</div>';
+  }
   try {
     await Promise.all([loadTasksForSettings(), loadHistoryForSettings()]);
   } catch (err) {