According to the [thispatcher] help file, a message of (window zoom 0, window exec) to [thispatcher] should restore the window to it's "unzoomed" size. However, it doesn't seem to work. I can't get the example in the help file to work either. "Zoom 1" works, just not "zoom 0."
The behavior of the zoom message is also different than if you actually click the little zoom button. The zoom 1 message puts the title bar of the window behind the menubar, while clicking the little zoom button puts the title bar right below the menubar.
I haven't tried this yet on a PC, just on my Mac, so all my comments above are related to the Mac platform. OS 10.5.8, Max 5.1.3.