Clear custom date fields inline editor


I’m using the edition by clicking directly on the cell, in this case the date field. When I click and open a calendar to include the desired date, when I clear the existing value, it is not clearing inside shows previous value


Could you clarify the question?
If the value is not cleared in the inline editor when trying to delete the value then please send an example to reproduce the issue.
If the inline editor returns the previous value of the task after closing the inline editor then this is the expected behavior of Gantt. For the task start_date and end_date are required parameters.
There is no built-in way to set an empty value to the date field, but you can implement it with the unsсheduled tasks which have no dates in Gantt. Please see this solution: Set empty value to date column onBeforeSave event.
It should be noted that in some scenarios (for example, when autoscheduling), Gantt expects that the task has a start_date, so if you delete the date, an error will appear.