Hi,
WS_MAXIMIZEBOX doesn't seem to work.
I tried to enable just the maximize flag on a dialog, but instead what I got was wine didn't letting the user change the dialog's size at all.
Cesar Mello coded a little example which shows this bug.
I filed a bugzilla report, you can see it and get the example app at:
http://bugs.winehq.com/show_bug.cgi?id=1338
Kind Regards,
Felipe