https://snippet.dhtmlx.com/2ojigjcn
It must be the compatibility with layout. The official example has the same issue.
https://docs.dhtmlx.com/scheduler/samples/10_integration/03_dhtmlxlayout.html
Hello @jyginger,
This is an issue on our end, thank you for noticing it. The dev team already works on a fix, and will try to release it ASAP.
Kind regards,