Docgen wizard : tree has invalid behavior

[etraisnel2]

"Generate documentation on selected elements" action provides a selection wizard
The tree has a weird behavior, propagation of checking seems to have a logic that is not only containement, but it doesn't use business rules either

See gif :

[etraisnel2]

Others issues :

Categories displayed (and checkable) even if they are empty) :

Element on left cannot be unchecked if it is not on the right and unchecked