Why is Print screen not working (ubuntu 17, gnome)?

Question

Gnome

In general, the question is pop. I googled, read, and no one can really explain anything.
There is a Print Screen key, there is a standard gnome-sreenshot tool, there are system settings where it is quite explicitly set that when you click on Print Screen, a screenshot should be taken. In addition, the help also states:
To quickly take a screenshot of the desktop, a window, or an area on the screen, use these global keyboard shortcuts:
Prt Scrn to take a screenshot of the desktop.
Alt+Prt Scrn to take a screenshot of the window.
Shift+Prt Scrn to take a snapshot of the area you selected.
But in fact, only Alt + Prt Scrn works, although everything is indicated in the same settings.
OK. Let it be. I'm trying to create my own shortcut key, for example alt + j
I write the command gnome-screenshot. In the end, it doesn't help either. Can anyone please explain what is going on? for example, if I write notify-send 123 for alt + j, it will work. However, if I do the same for the prin screen keys, then notify-send will not work.
ubuntu gnome 17.04

Answer 1

I did find the answer =P
In general, enabling Compose can help (at least as a temporary solution)
or in dconf along the path /org/gnome/desktop/input-sources/xkb-options you can add to the 'compose:prsc' array
If you think that this is a bad method or know how to explain exactly why this is required, then write. I didn't understand the problem 100%.

Answer 2

There is a suspicion that this may be due to the current keyboard layout (with a lot of unpleasant problems in GNOME). Try to switch to the English (US) layout

Answer 3

Turned on Compose. Because I don't need it, I hung it on ScrLock
And it all worked.
Thanks to the commentators above, I myself would not have guessed such a solution.

Answer 4

Ubuntu 20
It turned out to be quite simple:
Take a screen and copy it to the clipboard - ctrl-shift-prtsc
Take a screen and save it to the /Pictures folder - shift-prtsc