I think this is a bug that comes from the earlier versions of MailWasher Pro 2011.
I have 3 monitors on my computers (WinXP SP3).
MW always loads on the main monitor.
Then I click on the Minimize button and it moves from the main monitor to the monitor it was running when last shutdowned the computer.
Then I have to click again on The Maximize button and MW is full screen where It is supposed to run.
I hope I was clear enough.