Is "Create an actor filter page" sample code is correct?
Let's imagine you have a process "Europe"
in this process, you have a call activity to the process "France"
And then, in the process France, a call activity to the process "Grenoble".
In a task in the process Grenoble:
* the getProcessInstanceId() return the processID in the process Grenoble
* the ParentProcessInstanceId() is the processinstanceID in the process France
* the RootProcessInstanceId() is the processinstanceID in the process Europe (this is the case ID the user see)
You can use LongBoard (https://community.bonitasoft.com/project/custom-page-longboard) to understand and see the different processnstanceid
If you need to access the ParentProcessid, then you have to use the ProcessAPI (hum, saying that, I don't see the way to access the Parent in ProcessAPI - search or a containerId)
Hope this help,