Parent Id is missing in $bean

Hi Everyone,

I am working with the lead and custom module. From the details view I have added an action and on click of that my custom modules opens.
The problem is in $bean I am not getting the value of parent_id. whereas parent_type and parent_name are available.

[parent_name] => XXXXXXXX
[parent_type] => Leads
[parent_id] =>

Any suggestions guys?