Ok, I took the opportunity to mess with it a little more while I was home for lunch.
I think the task bar has to be set to the playfield, someone brought up such as issue with Hyperpin or fplaunch not that long ago. Try setting it to the playfield and see if it works.
I moved the taskbar back to display 1 (and double-checked that my playfield is, in fact, display 1), and tried the settings several different ways again, but still got the same results as before.
On a whim, I tried moving the explorer window from which I was launching PinSelect from monitor 2 over to screen 1, ran it, and LO AND BEHOLD... it was different -- not right, but different: my playfield image was where it belonged, but now I had no backglass image! I tried the different settings again, and then I was right back to where I was before. This was puzzling me, but strange as it may seem, I figured out that it must depend on which screen my mouse pointer is located when I launch PinSelect! If my cursor is on the playfield display, then that's where both images go, and if it's on the backglass monitor, then that's where the images will display. Or something along those lines... I had to hightail it back to work, so I didn't get to do any further diagnoses.
Any more ideas?
EDIT: I should mention that it doesn't seem to make a lick of difference what the Primary and Secondary settings are, as long as they're numbers. The words "Primary" and "Secondary," however, cause both images to be on the backglass.
It should work if your primary monitor (playfield) is the one which holds the 'main' desktop including the taskbar all other monitors should be only an extension to the desktop. E.g. if you have a three monitor setup screen1 is you main desktop with taskbar (playfield), screen2 (backglass) extends screen1 and finaly screen3 (DMD) extends screen2.
So if you start PinSelect from screen1 it should work, well at least it works on my cab and on my desktop in that way 
On a second thought I'm going to release v1.8 now, and you can try it. I'll try to find a better way detecting primary/secondary screen and make a bug fix version asap...
ok checkout post#1 for v1.8.
It introduces a simple attract mode together with the possibility to launch the last played table from the exit screen (thx jasonsmith for the nice idea
)
Edited by fuzzel, 24 April 2013 - 09:55 PM.