Inline editing date type delete

Hello. I have a question.

Can I enter the date type once in gantt inline editing and delete it?

If you enter it once and then delete it again, it becomes 1899-11-30.

Hello Seungmin,
The inline editor uses the Date type of the input element. That HTML element is rendered by the browser:
So, when you press Delete the data is cleared there and the browser adds a default value.
Please, clarify how you expect it to work. And what should happen after the date is deleted?