Geany

Great that it's cross-platform. Cute genie bottle icons. Unlike the program Notepad++, Geanie can natively compile/build/run workflow for code. There's a project panel, and good access to file trees/directory. I tend to work with numbers of text files at once, and prefer to be able to rename files from a directory, so I go with the heavier program Kate.

I am searching for a good Notepad++ alternative since I switch to Linux Mint. I finally find it. I compile it from source code and when I opened it for the first time, it remind me the good old Notepad++ experiences. It have a built in color selector and I am sure I am going to use it a lot.

Nice and lightweight (50mb downloaded on Windows, compared to 15mb for Notepad++). Just as fast and responsive as Notepad++.

The appearance is probably more customizable in Geany, but it's GTK.

Either one of these apps should give you what you need.

An alternative is Kate, but it's like 500mb. Still fast though, and it not only has tabbed, but windowed screens, which is useful (though most people probably would rather their window managers take charge of that outside of Windows).

Another alternative is VIM, if you're willing to learn all the key bindings. There is also a gui version of VIM.

You should definitely try it on Windows too and compare with other similar applications like Notepad++.

My go to for coding nowadays. I'm still learning vim, I like integrating everything together without it building up in large sizes. It's fun. So basically what I'm trying to say, is that this application called Geany is very close to Notepad++. It's basically Notepad++ but more stable (if you know you know) with unfortunately less of a community for plugins in comparison to notepad++. That being said, there's always room open out there for more contribution to cool little nifty plugins. Though, the current plugins that you can find on the official documentation wiki for Geany itself are pretty essential kind of plugins alone. So yeah, have fun. This thing gets the job done like I want it to. I actually used to be quite skeptical of it back then, and by back then I mean 1-2 years ago. Software is cool.