TreeSelect feature request

Discussed in https://github.com/orgs/primefaces/discussions/1298

^{Originally posted by rdyava February 26, 2024}
Hello all,

I am using the TreeSelect component and was wondering if there is a way to alter the behavior of the checkbox selection mode. Currently when there is a single child node of a parent node, with the checkbox selection mode enabled and selecting the child, it also checks the parent node as well. Is there a way to make it so that for this sort of use case, the parent node is not selected? For example, in the example in the documentation, selecting "Invoices.txt" also selects "Home", I would need "Home" to be a partially selected value in this case and not showing as a selection with "Invoices.txt".

The propogateSelectionUp and propogateSelectionDown props from the standard Tree component which modify the checkbox selection behavior are not present in the TreeSelect component. For my use case which I defined in the linked discussion, I would like these props to be made available in the TreeSelect component if possible.

Start with the TreeSelect component and compare its checkbox selection behavior with the standard Tree component's propogateSelectionUp and propogateSelectionDown props. Done means TreeSelect exposes the requested controls and selecting a sole child can leave its parent partially selected rather than selected, matching the described use case.