The new UI is almost as great a departure as was BFD1 to BFD2.
I have to say though I think the work flow is very much improved.
I didn't like the new UI much at first but it has grown on me. I was all for keeping the kit view but with hind sight I only ever really used it to access kit piece parameters that are now much more accessible with the new, "tech/Model" tabs you can see on the left. I do still think BFD2 is sexier and as frivolous as I know eye candy is, it does matter in terms of sales.
Not sure I'm allowed to say whether it's resizeable but if you look to the left of the, file/tool/help menus you'll see two arrows
pointing in opposite directions.
I'll let you do the math as to what they do
Steve