TLcyTreeTableViewAddOn does not have any API to customize the tree table view.
To modify the tree table view, you can:
Modify the configuration file: the configuration file of the add-on allows a few minor modifications, such as removing or replacing buttons in the tool bar.
Modify the source code: the source code of the add-on is available as sample code that comes with the Lucy distribution. You can replace the official add-on with the sample version, and make your changes in the sample code.
The class Javadoc of
TLcyTreeTableViewAddOncontains instructions on how to replace the add-on with the sample code version.