Refers to the instance of the style definition class which is the owner of
this style definition object. The owner is the top-level class in the chain of style
definition classes. Through this member, all rules and other members defined in the owner
definition class can be accessed.
Returns O | undefined
$parent
get $parent(): P | undefined
Refers to the instance of the style definition class which is the parnt of this style
definition object in the chain of style definition classes. Through this member, all rules
and other members defined in the parent definition class can be accessed.
Default styles that will be used by the Popup if styles are not specified using options.