Seems to me that we need to find ways of bringing this sort of thing to people's attention more readily.
Would a set of 'tips' that appears on startup be the answer, I wonder?
There's so much in BrainStorm that is documented in the help file ... but, by and large, people tend not to go there.
Shift and drag, for example, is the fastest way to make entries subsidiary to another entry. And, if you ctrl/select them in the first place, they end up in the sequence they were selected.
You can also shift/drag them to a heading to make them part of the heading's list.
On the split windows stuff, we have some nice improvements coming, including the ability to create a new window with the current entry as its heading. More on that later...