Since there will be no dates shown in calendar, the usual start and end datetime fields cannot be used.
In order to have this feature fully operational, there are three other extra fields to be included in the business model, so that the Start and End dates (DateTime fields) can be completely hidden from the user interface, these are:
The first one will be used to temporarily store the date & time clicked by the user, and this value will be internally passed to the Starting Date, Ending Date, Starting time and Ending time fields.
These 3 fields must be placed in the Table List (FullCalendar) columns AFTER the background event field, and set as invisible.
Now, in the event form interface, there's only the need to have the fields that control the Start and Ending Times of an event.
All the remaining dates (start and end) can be filled using these 2 values, using DF formulas in Genio.
Formula (DF) example for Starting Date:
CriaDataHora(DateFloorDay([DIARI->DTSELECT]),[DIARI->HRINI])
3 Extra fields needed on table list columns (FullCalendar) example:
Event Form example using noDates: Only 2 time fields are needed to control the event start and end times:
New event final result, on calendar interface: