What are your favorite gui editor (not just vim/emacs in console) for Linux that are not based on Electron and that are doing well with several langs?

I would have to say gvim.

Gedit and Sublime Text.
Didn't use sublime in a while, because some of the configuration-features didn't work as they should.

IntelliJ IDEA if we're talking about IDEs.

Leafpad if we're talking simple editors

@Jilano

It doesn't look like it, but that's absolutely no problem for me. I use xterm more than any other piece of software on my desktop.

Geany! It's awesome!

GTK based, and really fast and simple

Takes a little bit of effort to configure if you have specific needs

Depends on the job. GVim for some plaintext based magic in the configuration files, CherryTree for anything that needs more structure, VS Code for quick code editing... Anything more complex is probably done with something from JetBrains.

Tough question because I've been using vim for so long. But for a GUI editor, perhaps I'd look at Sublime or VS Code. And curse about how long it takes to load the fucking thing while vim has pretty much the same functionality but loads pretty much instantly. Just my €0.02 though ¯\_(ツ)_/¯

Sublime Text in every aspect