... or so it seems. This is new to me; I've been using the nVidia nview desktop manager for some time and not noticed anything "wrong" with its behaviour and Notepad++, but now - at least with nview 140.75 - anytime I try and close a Notepad++ tab/file the application moves from the display it was opened on to the "home" screen, which in my case is the centre (#2) screen, and the Save pop-up window moves to the top left of that display. In fact, even when I have Notepad++ maximized on my centre display, closing a tab/file will cause Notepad++ to resize to the left half of the screen - presumably because I have enable Gridlines in nview.
Note that disabling nview settings for the application doesn't help, and only disabling the desktop manager completely makes the problem go away.
Perhaps this is actually an issue with nView, though I suspect not as I don't seem to be having issues with other applications. Perhaps something related to having 3 displays (I only had 2 with my previous video card) - but that implies something related to the underlying Windows driver etc.
Anyone had any issues like this before? Windows 7 Pro.
I've been having exactly the same issue (3 monitors, latest nview 140.75).
Thanks for associating the two though, I've tried installing previous versions of npp but to no avail.
Disabling the desktop manager solved it as you've mentioned (but I guess that's not a real solution)
I was able to fix the issue by disabling "Add nView options to system menus" under User Interface in the nView Desktop Manager. This setting adds another item to the context menu when you right click the np++ title bar.
Looks like a bug with np++ not liking the title bar context menu being modified.