titleExpression property
getter/setter pair
The Arcade expression used to populate the callout title for showCalloutForGeoElement.
When set, this expression takes precedence over title for geo-element
callouts. The current geo-element is assigned to $feature. For
DynamicEntity geo-elements, the expression is re-evaluated as the
dynamic entity changes while the callout is open.
When unset, title is used as the fallback title source.