want only see the coding stuff

Maybe, but at least for the way I have things set up, not much is eliminated and a lot of non-coding stuff remains.

fail to see its usefulness.

Maybe was introduced to satisfy the want only see the coding stuff purists :)

You can post it on any place on screen with any size you currently have.
No need of fullscreen

Ah, hadn’t tried with anything but fullscreen (really tough to use N++ without it being fullscreen). Post-it works better that way, but still I rather fail to see its usefulness.

and I still see the plus sign.

Ah, okay, yeah, I see it now, too…it is oddly placed; it looks like it belongs to the FunctionList window and not the entire app.

clicking on that + will revert to normal.

Ah, that works for Fullscreen mode (although the use of a + in this case is kind of strange).

In Post-it mode, however, I have no such +. My Post-it mode looks rather odd; I’ve always wondered if it is correct (meaning what others see when they try it).

Really not sure what Post-it is supposed to provide, over or versus Fullscreen…

But here’s what I see in Post-it, note things (text GUI elements) around the borders are chopped in half… :

(But this is when I am remote-desktopped in from another machine to my Windows machine, so that may be influencing GUI aspects. I think that’s standard, but take it with a grain of saltpeter.)