Well, another great idea......but.......
I followed your directions to the T. The value for that setting was 321, not what you expected, huh? I went ahead and changed it to 375, but nothing moved, and I still can't drag the window over. Very weird. I hope the solution isn't something really stupid, as in I failed to see something obvious -- my face will be very red. I'm keeping my fingers crossed that Thom will say, "Eureka! it's a program glitch!" But it probably isn't.
By the way, on the Email tab of the Lots window, I can drag the border between Received and Sent up and down no problemo.
Thanks for the ideas, Garry.