Sorry to push an old report, but there is a topic buried inside of Windows Bugs thread, which might be missed:
http://www.purebasic.fr/english/viewtop ... indow+size
In practice the window size does not appear to be saved and it returns to the default values when the .pbf is re-opened.
[Done] Saving window size
Re: Saving window size
Already fixed for beta 8.