When the slotByElement method is used for multiple elements this could lead to performance issues in Scheduler.
For example, the difference in the performance can be observed in the Dojo examples linked below when loading the Scheduler and when changing the selected resources:
Dojo with 2023.1.314 - https://dojo.telerik.com/@NeliKondova/UJOcEJoC
Dojo with 2023.1.425 - https://dojo.telerik.com/@NeliKondova/UHisivuC
The issue occurs starting with the 2023 R1 SP1 release and could be due to the following fix - #7260