Remove connection between checked states of parent and children in ControlsFX CheckTreeView

I'm using CheckTreeView to represent hierachical structure. The current checking behaviour is if I check/uncheck a parent, all of its children will automatically get check/unchecked. If I check/uncheck all the children the parent also gets automatically checked/unchecked. Is there any way to remove this behaviour? I want to be able to select all the children without changing the checked state of the parent to true. I also want to be able to check the parent and some children but not all of them.