Update component window of a custom component in lazarus

[gayathri]

Hi all,
I am in need of creating a simple layout component in lazarus.
I would like to have a component window like TFlowpanel where on adding child components , a list is created and each item, is mapped to the list entry.
I looked into the code of tflowpanel, but could not trace where the component window and property windows are getting updated.
I have attached the desired component structure needed for me.
Kindly help me out to solve this issue

Thanks in advance!