Tree Children allways allowed in vaadin8?

hi there,

Maybe this is the dumbiest question of the day but, there are allways children allowed for Tree or TreeGrid in vaadin 8? As there was a method in vaadin7 which you can easily setChildrenAllowed(false/true), in vaadin8 I had not find any way to make it. Did I miss something? Maybe there is a new method in the TreeData or in the HierarchicalDataProvider?

Thx for the help.