Is there a relationship between selecting a node and selecting its parent node?

For example, if Node A has child nodes B, C and D, is it the case that selecting all of B,C and D implicitly selects A and vice versa?  If so, then you don't necessarily need different click behaviors for leaf and branch nodes.  Perhaps the first click on "Node A" expands it, and subsequent clicks select / deselect it (and all its children); and if B, C and D are each checked individually then A is checked automatically.  You would still need a separate button / triangle to collapse the list, but that functionality is much less important, especially if the list is only on screen transiently.

I am thinking here of the hierarchical checkbox lists you sometimes see in older Windows installer applications.  You get a list of features, with a checkbox next to each, and if the feature has sub-features of which only some are selected, its checkbox shows a special intermediate state.  I don't recall which installer type does this, and it's not brilliantly implemented anyway, but the basic idea can work well I think.

How to 'select' menu items that also link to deeper items?
Some people say since "so" is a transitional word, it should have a comma after it like all the transitional words have. And some say if "so" is there for logical continuity, then no comma should be used.

The particular sentence I am writing is:


  Moreover, I have completed my senior secondary studies in English and won 1st place at the regional stage of English Olympiad. So, I am confident that I will be able to complete a degree in English.

