Perhaps related in some way:
I find on Mac that if you save the Squeak window when it is bigger than the main display by extending onto a second screen, on restart the Squeak window size reverts to only a maximum of the main screen size.

Ken G. Brown

>Date: Sun, 09 Mar 2008 17:37:59 +0900
>From: Yoshiki Ohshima <yoshiki at vpri.org>
>Subject: [squeak-dev] Saving fullscreen flag
>To: The general-purpose Squeak developers list
>	<squeak-dev at lists.squeakfoundation.org>
>Message-ID: <uzlt8pa1k.wl%yoshiki at vpri.org>
>Content-Type: text/plain; charset=US-ASCII
>
>  BTW, does anybody else experience that the full screen status is not
>preserved upon saving and loading on Windows with using 3.10.6 VM?
>(The flag is set in the image on the disk but the VM doesn't seem to
>use it.)
>
>-- Yoshiki