Hi Jim,
Greetings from Syncfusion support.
We would like to inform you that, the selection performance issues of Grid in wasm application, occurs due to component re-rendering, when callback method is assigned to grid events. We have already documented a topic for improving the performance of Syncfusion Grid when using wasm application.
We suggest you to refer the below documentation for more details regarding improving wasm performance.
Please get back to us if you need further assistance.
Regards,
Renjith Singh Rajendran