I found the documentation for validation: https://neos.readthedocs.io/en/stable/References/Validators/Flow.html?highlight=earliestDate#datetimerangevalidator.
What I would like to do is validate that property begin is not empty and property end is not prior property begin. Validation for begin is fine. But validation vor end does not do anything. Setting earliestDate: now/P2W has no effect at all.
properties: begin: type: DateTime ui: label: 'Start' inspector: group: duration position: 10 editorOptions: format: 'd-m-Y H:i' validation: 'Neos.Neos/Validation/NotEmptyValidator':  end: type: DateTime ui: label: 'Ende' inspector: group: duration position: 20 editorOptions: format: 'd-m-Y H:i' validation: 'Neos.Neos/Validation/DateTimeRangeValidator':
Is there any example for this?