Performance issue with Scheduler module on Chrome after recent update

[Romain DEVAUX]

Hello,

I'm experiencing significant performance degradation with the Syncfusion Scheduler component since a recent update. The issue is specific to Chrome – Firefox performs perfectly without any lag.

Symptoms:

The UI becomes extremely sluggish when scrolling through the scheduler and when dragging tasks to new positions. The entire browser becomes unresponsive during these interactions. The problem is more pronounced with large datasets (many resources and tasks), though it occurs even with moderate loads.

Configuration:

The scheduler is implemented with custom wrapper code on top of the Scheduler component. Virtual scrolling is currently disabled, but enabling it doesn't resolve the issue. We're working with large numbers of resources and tasks.

Key Details:

This regression started after a recent Syncfusion update. Notably, Firefox shows zero performance issues with identical data and configuration, which suggests the problem is Chrome-specific or related to how Syncfusion handles DOM rendering in Chrome.

Questions:

Are there known performance issues with the Scheduler in Chrome after recent updates? Do you recommend any Chrome-specific rendering optimizations or configurations? Could there be a memory leak or excessive DOM manipulation in the latest version?

Please find attached a download link for two videos demonstrating the performance difference between Chrome and Firefox : https://transfer-vinci-energies.netexplorer.pro/share/0VJi7QXSExcmmarA195ANJvzwUQKP1

Thank you for your assistance!

[Vijayakumar Rajasekar]

Hi Romain,

 

Thank you for the detailed information about the performance issue with the Syncfusion Scheduler in Chrome. We understand this is impacting your application, and we're here to help resolve it.

 

We tested the Scheduler with approximately 900 resources in both Chrome and Firefox, with virtual scrolling enabled and disabled. We were unable to reproduce the performance degradation in our environment.

 

To diagnose this accurately, please provide the following details:

 

1. Versions: Which Syncfusion version before/after the update? Your Chrome version?

2. Data Scale: How many resources and tasks? Which view mode (Day/Week/Month)?

3. Console Errors:  Any errors in Chrome Developer Tools during the lag?

4. Environment: Does it occur in Chrome Incognito mode? Any Chrome extensions active?

5. Code Sample: Can you share your Scheduler configuration or a simplified sample?

 

We can also share our test videos (covering Chrome and Firefox scenarios) for comparison. Also please find the below sample for reference

Sample: https://stackblitz.com/edit/angular-2nd9rspy-uvmbjhms?file=src%2Fapp.component.html

We’re committed to resolving this issue and ensuring smooth performance in Chrome.

 

If there’s anything else we can assist you with, please let us know.

Regards,

Vijayakumar R

Attachment: Performance_243fbac1.zip

[Romain DEVAUX]

Hi Vijayakumar,

Thank you for the follow-up. We've compiled detailed information about our environment and the performance issue. Here are the specifics:

- Syncfusion: 32.2.3 (@syncfusion/ej2-angular-schedule)

- Chrome: Latest (tested in Incognito mode)

- Firefox: Latest (performs perfectly)

- Angular: 21.2.9

- View Mode during testing: TimelineWeek with hourly granularity (custom view combining TimelineWeek with hourly slots - ViewIndex.WeekHour)

- Number of resources: Approximately 50-100+ resources in test

- Virtual scrolling: DISABLED (tried enabling, no improvement)

- Drag & Drop: ENABLED

- Resizing: ENABLED

Configuration from our component:

// TimeScale configuration for WeekHour view
timeScaleWeekHours = {
  enable: true,
  interval: 60, // 1-hour interval
  slotCount: 1,
};


// Component properties
rowAutoHeight = true;
virtualize = false;
allowDragAndDrop = true;
allowResizing = true;
group: GroupModel = {
  enableCompactView: false,
  resources: ['Plannings', 'Resources']
};


// Scheduler template binding
<ejs-schedule
  allowDragAndDrop="true"
  allowResizing="true"
  [rowAutoHeight]="rowAutoHeight"
  [enablePersistence]="false"
  [timeScale]="timeScale"
  [currentView]="$currentView()"
  (dragStop)="onTaskDragStop($event)"
  (dragStart)="onTaskDragStart($event)"
  (resizeStart)="onResizeStart($event)"
  (resizeStop)="onResizeStop($event)"


No errors in console, no abnormal delays in network tab or no memory leaks visible in chrome devTools.



The issue appears random/intermittent and is most noticeable during:

- Scrolling through the scheduler (particularly in WeekHour view)

- Dragging tasks to new positions

- The browser becomes completely unresponsive during these interactions

- Firefox (identical configuration & data) shows zero lag

We have limited ability to create a simplified StackBlitz sample due to the complexity of our wrapper implementation and custom event handlers (context menus, drag/drop overrides, custom popup handling).

Could this be Chrome-specific rendering optimization with the recent Syncfusion update ?

Thank You,

Romain

[Vijayakumar Rajasekar]

Hi Romain,

 

Thank you for sharing such detailed configuration information — we truly appreciate the effort you've put into documenting this.

 

We have carefully analyzed your setup and updated our sample to closely match your reported configuration, including:

 

• TimelineWeek view with interval: 60 (1-hour slots)
• rowAutoHeight: true
• allowDragAndDrop: true and allowResizing: true
• Two-level resource grouping (Plannings → Resources)
• enableCompactView: false
• Virtual scrolling disabled

 

We have recorded a video demonstrating the sample running in Chrome with the above configuration, and we were unable to reproduce the performance degradation in our environment.

 

Please find attached:

• Updated StackBlitz Sample — reflecting your configuration: https://stackblitz.com/edit/angular-2nd9rspy-qvna3msn?file=src%2Fapp.component.ts
• Recording — showing Chrome performance with your setup

 

We would like to check if there are any configuration details or custom behaviors that may not be reflected in our sample. Could you help us by confirming the following:

 

• Custom drag/drop handlers — Does your onTaskDragStop or onTaskDragStart perform any API calls, state updates, or UI operations?
• Context menu — Is a custom context menu attached to the scheduler?
• Wrapper component — Does your custom wrapper have any additional mousemove or scroll event listeners attached?

 

These details will help us replicate the exact environment and identify the root cause more precisely. We are committed to resolving this and will keep you updated every step of the way.

 

Please let us know if there is anything else we can assist you with.

 

Regards,

Vijayakumar R

Attachment: PerformanceLatest_cd6da978.zip