For me, ADE17.2 just opens the same size as it was when I last closed it.
So once set it to the appropriate size and it should stick there.
If you want to change between a set of sizes I am sure there is free window management software out there to help,
but I can't think of any off the top of my head.
I see AutoSizer http://www.southbaypc.com/AutoSizer/ (free)
and zmover http://tucows.com/preview/402638/ZMover (not free)
in a quick web search. Not tired either, and I am sure there are many more.