I also have 2 monitors, but my secondary monitor is on the right. I thought that Windows does this, and not Fences?
Does Fences do this for you even if there is plenty of space left on the main monitor? My main monitor is full of icons, so I kind of thought this may be happening, because it main monitor is full, thus new icons go to the 2nd monitor. But now, not so sure this is how it should be...