Hi Juan,
Thank you for contacting Syncfusion support.
We have checked the last reported issue “Sub menu items are not shown while rending self-referential dataSource with custom menu fields” by preparing sample based on the attached screenshots and we can reproduce it in our end.
We confirmed this as a defect and the fix for this issue will be included in our first EJ2 patch release after Essential Studio 2019 Volume 1 main release.
We will update you with the sample once the patch release has been rolled-out and, we appreciate your patience until then.
Note:
If you want the vertical menu, we suggest you to use the property ‘Orientation’ as ‘Vertical’. Please refer our below demo sample for more details.
Regards,
Silambarasan