When a Date is already present in the DateTimePicker and the date parts are focused with a mouse click the digits for the year part are cut off.
Reproducable in this Dojo.
Screen recording of the issue.
The DateTimePicker's popup calendar view is cut in the Default, Classic, and Fluent themes.
The Date and Time views in the DateTimePicker popup are trimmed.
The Date and Time views in the DateTimePicker popup should not be trimmed.