sometimes I really have to look to find it’s secret pop-up location!
points to the Find Dialog’s stealthy appearance
I use 4 monitors as well most of the time, and I have no such problems. There are no secrets/stealth operations here – the Find dialog will remain where YOU last put it. There should be no need to go hunting for it, just don’t put it in a different location at different times – and if you do, remember where that was.
if <Ctrl-F> could at least open the dialog on the same monitor
Think of how many users that would not want that; I’m one of them. I’ll go out on a limb and say that most users of 2+ monitors have N++ full-screen on one of them, and a Find window appearing on that, right in the way of the text they are editing, would be terribly annoying as they now have to grab that Find window and move it somewhere else, to see their text behind it.