Conditional display in calendar

How can I do to view events in the calendar only with certain conditions? I have a table with records including a data filed and a status field (multiple choice). I would like to display in the calendar only the events that have certain values in the status field. I tried @Birger  formula but it doesn't work:

Birger H
Master (1507)

Tuesday, July 17, 2018 11:43 AM
Create a new date or appointment 'My Date' field.
Give the property "Display in Calendar" = true.
Fill this field on the "onChange" trigger of the 'Status' field like this:

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'My Date' := null;
'My Date' := if text('Status') = "open" then 'Date field' end 
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