Thanks to some previous questions [1, 2] I've managed to solve one of the more pervasive issues I and others have had with N++ which is the way it handled tab shifting in most recently used order rather than simply visual order.
A lot of the advice suggest you disable both check boxes even though only one indicates MRU Order. Why is that? I'd test it myself but I'm not going to be on windows for a few weeks and I'd like to be able to explain it to my tech supportees when they ask.
The first setting controls whether you'll get a document-switching window when you press Ctrl+Tab. That window appears when Ctrl+Tab is pressed and goes away when Ctrl is released (so you can press Tab multiple times to cycle over to non-immediately-adjacent documents). It looks like this:
If you uncheck that first box, that window and the MRU behavior (switching between the two most recently used tabs unless you hit Tab multiple times) will go away. That is, pressing Ctrl+Tab will then immediately switch to the tab to the right of the current one. Ctrl+Shift+Tab does the same, but left. Perhaps the people who recommend unchecking both boxes don't care for this window.
If you only uncheck the second box (Enable MRU behavior), you'll still have that switching window, but it will always go to the next or previous document (depending on Shift) on each press of Tab.
Perhaps the setting group would have been better named Document Switcher Window.
