Great stuff!
I suppose why i wasn't used to it coming from Ableton, is that Ableton lets you define the area up/down and left/right with its yellow shading which was more intuitive..
I will start using this though and see how I get on.
Still advocate proper Area Selection for arranging like Ableton and PT where you just shade over the area/items instead of a long column as in Reaper at the moment..
However until then i will try this