feat(task-management): enhance real-time updates and performance optimizations

- Implemented CSS styles to prevent flickering during socket updates, ensuring stable content visibility.
- Modified `TaskRow` component to improve loading behavior and prevent blank content during real-time updates.
- Enhanced socket handlers to update task management state immediately upon receiving real-time data, reducing the need for unnecessary refetches.
- Introduced logic to track loading state, ensuring consistent rendering and improved user experience during task updates.

worklenz-frontend/src/components/task-management/task-row-optimized.css

@@ -36,6 +36,22 @@
   will-change: transform;
 }
 
+/* REAL-TIME UPDATES: Prevent flickering during socket updates */
+.task-row-optimized.stable-content {
+  contain: layout style;
+  will-change: transform;
+  /* Prevent content from disappearing during real-time updates */
+  min-height: 40px;
+  transition: none; /* Disable transitions during real-time updates */
+}
+
+.task-row-optimized.stable-content * {
+  contain: layout;
+  will-change: auto;
+  /* Ensure content stays visible */
+  opacity: 1 !important;
+}
+
 /* Optimize initial render performance */
 .task-row-optimized.initial-load * {
   contain: layout;

worklenz-frontend/src/components/task-management/task-row.tsx

@@ -179,9 +179,11 @@ const TaskRow: React.FC<TaskRowProps> = React.memo(({
   scrollableColumns,
 }) => {
   // PERFORMANCE OPTIMIZATION: Implement progressive loading
-  const [isFullyLoaded, setIsFullyLoaded] = useState(false);
+  // Immediately load first few tasks to prevent blank content for visible items
+  const [isFullyLoaded, setIsFullyLoaded] = useState((index !== undefined && index < 10) || false);
   const [isIntersecting, setIsIntersecting] = useState(false);
   const rowRef = useRef<HTMLDivElement>(null);
+  const hasBeenFullyLoadedOnce = useRef((index !== undefined && index < 10) || false); // Track if we've ever been fully loaded
   
   // PERFORMANCE OPTIMIZATION: Only connect to socket after component is visible
   const { socket, connected } = useSocket();
@@ -200,16 +202,18 @@ const TaskRow: React.FC<TaskRowProps> = React.memo(({
 
   // PERFORMANCE OPTIMIZATION: Intersection Observer for lazy loading
   useEffect(() => {
-    if (!rowRef.current) return;
+    // Skip intersection observer if already fully loaded
+    if (!rowRef.current || hasBeenFullyLoadedOnce.current) return;
 
     const observer = new IntersectionObserver(
       (entries) => {
         const [entry] = entries;
-        if (entry.isIntersecting && !isIntersecting) {
+        if (entry.isIntersecting && !isIntersecting && !hasBeenFullyLoadedOnce.current) {
           setIsIntersecting(true);
           // Delay full loading slightly to prioritize visible content
           const timeoutId = setTimeout(() => {
             setIsFullyLoaded(true);
+            hasBeenFullyLoadedOnce.current = true; // Mark as fully loaded once
           }, 50);
           
           return () => clearTimeout(timeoutId);
@@ -227,10 +231,18 @@ const TaskRow: React.FC<TaskRowProps> = React.memo(({
     return () => {
       observer.disconnect();
     };
-  }, [isIntersecting]);
+  }, [isIntersecting, hasBeenFullyLoadedOnce.current]);
 
   // PERFORMANCE OPTIMIZATION: Skip expensive operations during initial render
-  const shouldRenderFull = isFullyLoaded || isDragOverlay || editTaskName;
+  // Once fully loaded, always render full to prevent blanking during real-time updates
+  const shouldRenderFull = isFullyLoaded || hasBeenFullyLoadedOnce.current || isDragOverlay || editTaskName;
+  
+  // REAL-TIME UPDATES: Ensure content stays loaded during socket updates
+  useEffect(() => {
+    if (shouldRenderFull && !hasBeenFullyLoadedOnce.current) {
+      hasBeenFullyLoadedOnce.current = true;
+    }
+  }, [shouldRenderFull]);
 
   // Optimized drag and drop setup with better performance
   const {
@@ -355,7 +367,8 @@ const TaskRow: React.FC<TaskRowProps> = React.memo(({
     if (!task.id) return;
     dispatch(setSelectedTaskId(task.id));
     dispatch(setShowTaskDrawer(true));
-    // Fetch task data
+    // Fetch task data - this is necessary for detailed task drawer information
+    // that's not available in the list view (comments, attachments, etc.)
     dispatch(fetchTask({ taskId: task.id, projectId }));
   }, [task.id, projectId, dispatch]);
 
@@ -898,7 +911,7 @@ const TaskRow: React.FC<TaskRowProps> = React.memo(({
         rowRef.current = node;
       }}
       style={dragStyle}
-      className={`${styleClasses.container} task-row-optimized ${shouldRenderFull ? 'fully-loaded' : 'initial-load'}`}
+      className={`${styleClasses.container} task-row-optimized ${shouldRenderFull ? 'fully-loaded' : 'initial-load'} ${hasBeenFullyLoadedOnce.current ? 'stable-content' : ''}`}
       data-task-id={task.id}
     >
       <div className="flex h-10 max-h-10 overflow-visible relative">
@@ -1039,6 +1052,9 @@ const TaskRow: React.FC<TaskRowProps> = React.memo(({
   if (prevProps.isDragOverlay !== nextProps.isDragOverlay) return false;
   if (prevProps.groupId !== nextProps.groupId) return false;
   
+  // REAL-TIME UPDATES: Always re-render if updatedAt changed (indicates real-time update)
+  if (prevProps.task.updatedAt !== nextProps.task.updatedAt) return false;
+  
   // Deep comparison for task properties that commonly change
   const taskProps = ['title', 'progress', 'status', 'priority', 'description', 'startDate', 'dueDate'];
   for (const prop of taskProps) {
@@ -1047,9 +1063,36 @@ const TaskRow: React.FC<TaskRowProps> = React.memo(({
     }
   }
   
-  // Compare arrays by length first (fast path)
+  // REAL-TIME UPDATES: Compare assignees and labels content (not just length)
-  if (prevProps.task.labels?.length !== nextProps.task.labels?.length) return false;
+  if (prevProps.task.assignees?.length !== nextProps.task.assignees?.length) return false;
+  if (prevProps.task.assignees?.length > 0) {
+    // Deep compare assignee IDs
+    const prevAssigneeIds = prevProps.task.assignees.sort();
+    const nextAssigneeIds = nextProps.task.assignees.sort();
+    for (let i = 0; i < prevAssigneeIds.length; i++) {
+      if (prevAssigneeIds[i] !== nextAssigneeIds[i]) return false;
+    }
+  }
+  
   if (prevProps.task.assignee_names?.length !== nextProps.task.assignee_names?.length) return false;
+  if (prevProps.task.assignee_names && nextProps.task.assignee_names && prevProps.task.assignee_names.length > 0) {
+    // Deep compare assignee names
+    for (let i = 0; i < prevProps.task.assignee_names.length; i++) {
+      if (prevProps.task.assignee_names[i] !== nextProps.task.assignee_names[i]) return false;
+    }
+  }
+  
+  if (prevProps.task.labels?.length !== nextProps.task.labels?.length) return false;
+  if (prevProps.task.labels?.length > 0) {
+    // Deep compare label IDs and names
+    for (let i = 0; i < prevProps.task.labels.length; i++) {
+      const prevLabel = prevProps.task.labels[i];
+      const nextLabel = nextProps.task.labels[i];
+      if (prevLabel.id !== nextLabel.id || prevLabel.name !== nextLabel.name || prevLabel.color !== nextLabel.color) {
+        return false;
+      }
+    }
+  }
   
   // Compare column configurations
   if (prevProps.fixedColumns?.length !== nextProps.fixedColumns?.length) return false;

worklenz-frontend/src/hooks/useTaskSocketHandlers.ts

@@ -74,6 +74,19 @@ export const useTaskSocketHandlers = () => {
         selected: true,
       })) || [];
 
+      // REAL-TIME UPDATES: Update the task-management slice for immediate UI updates
+      if (data.id) {
+        dispatch(updateTask({
+          id: data.id,
+          changes: {
+            assignees: data.assignees?.map(a => a.team_member_id) || [],
+            assignee_names: data.names || [],
+            updatedAt: new Date().toISOString(),
+          }
+        }));
+      }
+
+      // Update the old task slice (for backward compatibility)
       const groupId = taskGroups?.find((group: ITaskListGroup) =>
         group.tasks?.some(
           (task: IProjectTask) =>
@@ -98,9 +111,10 @@ export const useTaskSocketHandlers = () => {
           } as IProjectTask)
         );
 
-        if (currentSession?.team_id && !loadingAssignees) {
+        // Remove unnecessary refetch - real-time updates handle this
-          dispatch(fetchTaskAssignees(currentSession.team_id));
+        // if (currentSession?.team_id && !loadingAssignees) {
-        }
+        //   dispatch(fetchTaskAssignees(currentSession.team_id));
+        // }
       }
     },
     [taskGroups, dispatch, currentSession?.team_id, loadingAssignees]
@@ -110,11 +124,31 @@ export const useTaskSocketHandlers = () => {
     async (labels: ILabelsChangeResponse) => {
       if (!labels) return;
       
+      // REAL-TIME UPDATES: Update the task-management slice for immediate UI updates
+      if (labels.id) {
+        dispatch(updateTask({
+          id: labels.id,
+          changes: {
+            labels: labels.labels?.map(l => ({
+              id: l.id || '',
+              name: l.name || '',
+              color: l.color_code || '#1890ff',
+              end: l.end,
+              names: l.names
+            })) || [],
+            updatedAt: new Date().toISOString(),
+          }
+        }));
+      }
+      
+      // Update the old task slice and other related slices (for backward compatibility)
+      // Only update existing data, don't refetch from server
       await Promise.all([
         dispatch(updateTaskLabel(labels)),
         dispatch(setTaskLabels(labels)),
-        dispatch(fetchLabels()),
+        // Remove unnecessary refetches - real-time updates handle this
-        projectId && dispatch(fetchLabelsByProject(projectId)),
+        // dispatch(fetchLabels()),
+        // projectId && dispatch(fetchLabelsByProject(projectId)),
       ]);
     },
     [dispatch, projectId]
@@ -189,11 +223,12 @@ export const useTaskSocketHandlers = () => {
             }
           }));
         } else if (!currentGroup || !targetGroup) {
-          // Fallback to refetch if groups not found (shouldn't happen normally)
+          // Log the issue but don't refetch - real-time updates should handle this
-          console.log('🔄 Groups not found, refetching tasks...');
+          console.log('🔄 Groups not found, but avoiding refetch to prevent data thrashing');
-          if (projectId) {
+          // Remove unnecessary refetch that causes data thrashing
-            dispatch(fetchTasksV3(projectId));
+          // if (projectId) {
-          }
+          //   dispatch(fetchTasksV3(projectId));
+          // }
         }
       }
     },
@@ -611,13 +646,27 @@ export const useTaskSocketHandlers = () => {
     [dispatch, taskGroups]
   );
 
+  // Handler for TASK_ASSIGNEES_CHANGE (fallback event with limited data)
+  const handleTaskAssigneesChange = useCallback(
+    (data: { assigneeIds: string[] }) => {
+      if (!data || !data.assigneeIds) return;
+      
+      // This event only provides assignee IDs, so we update what we can
+      // The full assignee data will come from QUICK_ASSIGNEES_UPDATE
+      console.log('🔄 Task assignees change (limited data):', data);
+    },
+    []
+  );
+
   // Register socket event listeners
   useEffect(() => {
     if (!socket) return;
 
     const eventHandlers = [
       { event: SocketEvents.QUICK_ASSIGNEES_UPDATE.toString(), handler: handleAssigneesUpdate },
+      { event: SocketEvents.TASK_ASSIGNEES_CHANGE.toString(), handler: handleTaskAssigneesChange },
       { event: SocketEvents.TASK_LABELS_CHANGE.toString(), handler: handleLabelsChange },
+      { event: SocketEvents.CREATE_LABEL.toString(), handler: handleLabelsChange },
       { event: SocketEvents.TASK_STATUS_CHANGE.toString(), handler: handleTaskStatusChange },
       { event: SocketEvents.TASK_PROGRESS_UPDATED.toString(), handler: handleTaskProgress },
       { event: SocketEvents.TASK_PRIORITY_CHANGE.toString(), handler: handlePriorityChange },
@@ -646,6 +695,7 @@ export const useTaskSocketHandlers = () => {
   }, [
     socket,
     handleAssigneesUpdate,
+    handleTaskAssigneesChange,
     handleLabelsChange,
     handleTaskStatusChange,
     handleTaskProgress,