The multiselect.clear() method clears the list of selected events in the JavaScript Scheduler and updates the view.
DayPilot.Scheduler.multiselect.clear(dontRedraw);dontRedraw (boolean) - true if the scheduler should not be automatically updated using multiselect.redraw()
<button id="clear">Clear selection</button>
<script>
// ...
document.querySelector("#clear").addEventListener("click", () => {
dp.multiselect.clear();
});
</script>