Browser Freeze when loading a kml on Cesium with track with a few thousands points

1. A concise explanation of the problem you’re experiencing.

I am trying to display a KML file using Cesium, but when I load the file, my browser gets very slow and I can’t actually use it for a while.

The KML has a few hundreds of placemarks. It’s only a problem when I include the placemarks that have tracks. Those tracks have a few thousands points overall.

I’ve tried changing the options of the viewer, in particular disabling widgets and setting requestRenderMode to true, but nothing helped noticeably.

Thanks for any help you can provide!

2. A minimal code example. If you’ve found a bug, this helps us reproduce and repair it.

You can view my test page here: and you can get the KML there:

3. Context. Why do you need to do this? We might know a better way to accomplish your goal.

I want to display the route and the pins. The time widgets are nice to have but if it makes it fast without them, then they shall go. I have tried removing what I could from the viewer constructor options, but nothing helped.

4. The Cesium version you’re using, your operating system and browser.

Cesium 1.65, Firefox 71 64-bit on Linux Mint 19.