keyboard cursor keys keep popping up the screenshot
 

Fedora 25, i've been applying the updates. some time this problem arrears itself, i uninstalled gnome-screenshot, yet a every cursor key, alt key pops up message box Failed to execute child process "gnome-screenshot"

something is very broken with keyboard handling.
this problem is occurring with desktops LXDE,LXQT,kde plasma.
I've tried downgrading packages, but the problem persists.

I downloaded to source rpms for x11 and lxde,gdm etc....but this is all huge.
xorg have a lot of spec documents, but really i'm looking for a guide
to the code and architecture.
I would really like to know how to start to debug where the problem lies
any tips?

i think while you were trying to fix something it is now broken beyond repair.
please reinstall and be more careful in the future.

edit:
ok, that was too harsh.

all the software packages you mention have NOTHING to do with screenshots.
i also wonder how a screenshot command came to be assigned to a cursor key in the first place? certainly not standard.
i would start by examining the hotkey or keyboard shortcut functionality of your desktop environment (must be in settings somewhere) and see if you can unset the key that is still trying to trigger gnome-screeshooter.

Thanks for your input, so i did end up reinstalling Fed25,
I do recall seeing some app that was to do with assigning hot keys, I did clear the
Prnt Scn key, but none of it had any effect, something already was very broken. I'm unsure now what that app was,as
its not in the fresh install, you would think it would be just part of preferences set, but i can't see it.

BTW, even in Fed24, I consistently got the screen snapshot when i Ctrl-Ins for clipboard paste, that was only a bit
less anoying...btw,just because i use linux for all my c/c++,android,pic,avr etc dev work doesn't mean i'm a fan of the linux's desktops,
imho windows kills it,even compared to the old faithful XP. So many times the linux desktop hangs,and these days just reach for the powerswitch, its no longer fruitful even the ssh terminal from another machine, as stopping and restarting X/desktop
doesn't work so simply anymore.........
i downloaded those codes because i really think keyboard handling is not great in linux, and i'm half motivated to find
out why from the code perspective.....

hmm, that sounds wrong.
on my system it's Shift-Ins in the terminal, and Ctrl-V in graphical apps.

why do you insist on using fedora? it's a so-called bleeding-edge distro:
"a distribution developed by technologies incorporating those so new that they could have a high risk of being unreliable. No matter how much we want to use these distributions, they will always have stability issues."

You don't need that for coding.

By using fedora you are, effectively, a beta tester for redhat.

other distros can give you new releases of software whilst still remaining reasonably stable (and usable).