Additional condition(s) for filtering the data set. HQL is the expected here.

Start your filter name with e.customProperties. followed by the field id (i.e. title)

e.customProperties.title = 'Trip'

Hash variable is accepted here.

e.customProperties.submitted_by = '#currentUser.id#'

Userview Key can be used as part of the condition.

e.customProperties.category_id = '#userviewKey#'