PROBLEM FINALLY SOLVED!!!
I've allso been looking for a way to make new (and old) windows to have a smaller size than the default window size. So today I started google:ing to find a way, and I found this forum amongst others.
In one of these forums someone mentioned a software that might work. So I downloaded it and gave it a shot. To my suprize it did everything I wanted it to do. Set specific window-sizes (with both old and new windows), specify windows positions and so on.
My search is now over and I'm a very happy camper now that this anoying issue is finally solved. So do as I did and give it a shot.
Note that the program isn't freeware and you have to pay for it. If you're a poor fellow and can't afford to buy it there is another way of getting the full version. You'll probably figure out how by yourselves.
Get the free trial version here:
http://www.actualtools.com/windowguard/
Hope this will end your endless search as it did for me.