I set the cell's background color in onBeforeCellRender. After some user actions I have to change this background color. Therefore, I have to fire onBeforeCellRender again. Otherwise, maybe there is another way to do this?
You can either update the full scheduler using update(): https://api.daypilot.org/daypilot-scheduler-update/
Or you can update a row using rows.update(): https://api.daypilot.org/daypilot-scheduler-rows-update/
In most cases rows.update() will refresh all cells in the current viewport but it will be faster than a full update().