Global menu in GTK applications does not work

[Ernesto Acosta]

Hi guys. I'm having a rather curious problem with KDE Neon that does not 
happen to me in ArchLinux, for example. Applications like Firefox, 
Thunderbird or LibreOffice show me the global menu, however, others like 
GIMP or Inkscape do not. But, if I run GIMP or Inkscape in the terminal, 
if they show the global menu ..

If I put the file .profile, .bash or .zshrc the command: export 
GTK_MODULES = "appmenu-gtk-module" the variable is exported without 
problems, but for more than restart, the same thing keeps happening to me.

Any idea what is happening?

Cheers

Ernesto