How does Bamboo call and set UIConfigSupport/ UIConfigBean and why is it null in certain instances

I am new to Bamboo plugin development, base on instructions given here - https://developer.atlassian.com/server/bamboo/tasks-overview/#TasksOverview-ExecutableCapabilities, I am trying to use UIConfigBean to filter and populate my executable, but UIConfigBean turns out to be null in my case.
I have looked at other app implementation and have notices, they have a function setUIConfigSupport() and they have mentioned, Bamboo calls this function on instantiation of the configurator class. But in my implementation the function doesn’t get called, what am I missing? or how do I make Bamboo call this function?

Any lead or pointers will be very much appreciated. Thank you!