As it states in EZP-27901, there should be validation of required property on field DateAndTime.

Prerequisites

1. Content type with two fields:
   1. String - Name
   2. DateAndTime with property Require and Empty

Steps:

1. Go to Content > Content structure > Create
2. Click link with content type from Prerequisites
3. Click on DateAndTime field
4. Click outside the datepicker to lose focus

Actual result:

Datepicker dissapears, no validation.

Expected result:

Datepicker dissapears, field has red validation border on and message.

%field_name% field is required