You mean hold click and drag over slots to make a selection which should be used for event creation, right? I'm interested, because I wanted to ask for the same functionality.
Currently, the following scenarios are not supported, I can recommend submitting a feature request in our feedback portal where new ideas are constantly being evaluated:
Please vote for my feature request: https://feedback.telerik.com/kendo-react-ui/1584271-scheduler-to-support-more-control-over-slot-selection