dhxCalendar custom values/buttons

I would like to add custom buttons to the dhxCalendar.This is to restrict the users to choose either a date or click on one of the custom buttons with the “tbd” or “ongoing” value.

What is the best approach to do that?

There is no built-in support for adding custom buttons into calendar.
You can try to inject custom HTML inside calendar area as it show here - dhtmlx.com/docs/products/kb/inde … 20calendar