Form.Left And Form.Top To A Different Screen Don't Work?

I've run into a little problem recently. My computer has two screens sitting side-by-side.

Here are the dimensions for my first screen: {X = 0 Y = 0 Width = 1280 Height = 1024}

Here are the dimensions for my second screen: {X = 1280 Y = 0 Width = 1280 Height = 1024}

My form saves its position on exit into the Registry. Whenever I start my application, I set its opacity to 0 in the constructor and it goes to my first screen. While its opacity is at 0, I then move it to its previous location (1280, 0) like this:

thisForm.Left = X
thisForm.Top = Y
Where X = 1028 and Y = 0.

I place a breakpoint directly in front of those assignments and when I hover over thisForm.Left, it = -4. Whenever I hover over thisForm.Top, it = -4.

Sure enough, when my form comes up, it's in my first screen.

For those interested, I've now worked around it, by doing some additional testing. What caused it: My Window State was Maximized. Solution: If before I set these positions, I change my Window State to Normal, the form moves. I can then maximize it while it's on the second screen and it remains there. why I can't move my form while it's maximized? It's more for curiosity than to find a solution, since the work-around is actually working quite well.