Pasting on repeat is really slow

I’m not sure if I’m doing something wrong, but if I copy 5 lines, and then hold down ctrl-v to paste the lines repeatedly, CM gets really slow while Monaco stays zippy fast.

Video of CM:

Video of Monaco (in VS Code):

My CM setup is basic:

new EditorView({
  extensions: [basicSetup, javascript()],

I tried to reproduce this here, but it remains entirely speedy for me.

It happens to me there too:

My system:

  • MS Edge 119.0.2151.72
  • macOS 14.1.1 on MacBook Air M2

In Safari it is faster, but still not as fast as Monaco. Here’s Safari (when I move the mouse near the end, I already let go of cmd-v, but it is still catching up):