Describe the bug
The Native Scheduler allows you to create a new event without setting a title for it. When such an event is created, its delete (X) icon cannot be clicked.

The issue is replicable in scenarios with both default rendering of a custom SchedulerItem.

To Reproduce

1. Open this StackBlitz example
2. Double-click on the Scheduler to create a new event
3. Enter a value in the description field and save the new event

Expected behavior
When you try to delete the event that has no title, you should be able to do it

Workaround
Use the following CSS definition to workaround the bug:

div.k-scheduler-body > div > span.k-event-actions {
  z-index: 30000;
}

Here is a StackBlitz example demonstrating the usage of the above CSS.