What I'm looking for:

• lightweight (non IDE) program for Linux that manages the tasks listed below
• modern GUI program - I want to use mouse, drag-n-drop, …

It should be gratis software.

The features from Notepad++ I want to use in the desired Linux program (from the most important ones):

• multiple files open in tabs
• syntax highlighting for most languages
• toggle comment for most languages
• regex find and replace
• reload prompt if the file has been modified outside the program
• autosave
• find and replace in all opened files or all files in directory
• simple autocomplete (based on other text in the same file)
• hex editor

Is there any program on Linux that matches these requirements, or nearly all of them?

EDIT - Atom:
I've tried the first recommendation - Atom. Although I support the effort put into that editor, it fails to satisfy my needs for many reasons:

• Very cumbersome key bindings
• editor freezes when used after a longer time
• no show printable characters button
• UI - maybe I didn't understand it well, but why I slide right in the editor while clicking left on scrollbar?
• regex replace is terribly slow, even if the file has less then 1000 characters

I haven't tested any other feature, because the slow regex replace discourage me on its own from using the editor. Atom could be a great text editor once, but now it's not in "release state" if you ask me.

What I'm looking for:

• lightweight (non IDE) program for Linux that manages the tasks listed below
• modern GUI program - I want to use mouse, drag-n-drop, …

It should be gratis software.

The features from Notepad++ I want to use in the desired Linux program (from the most important ones):

• multiple files open in tabs
• syntax highlighting for most languages
• toggle comment for most languages
• regex find and replace
• reload prompt if the file has been modified outside the program
• autosave
• find and replace in all opened files or all files in directory
• simple autocomplete (based on other text in the same file)
• hex editor

Is there any program on Linux that matches these requirements, or nearly all of them?

EDIT - Atom:
I've tried the first recommendation - Atom. Although I support the effort put into that editor, it fails to satisfy my needs for many reasons:

• Very cumbersome key bindings
• editor freezes when used after a longer time
• no show printable characters button
• UI - maybe I didn't understand it well, but why I slide right in the editor while clicking left on scrollbar?
• regex replace is terribly slow, even if the file has less then 1000 characters

I haven't tested any other feature, because the slow regex replace discourage me on its own from using the editor. Atom could be a great text editor once, but now it's not in "release state" if you ask me.

EDIT - Sublime Text: Although it looks fine, I noticed that Sublime Text is not gratis. Now (2016-12-23), they want a 70$ per license.

What I'm looking for:

• lightweight (non IDE) program for Linux that manages the tasks listed below
• modern GUI program - I want to use mouse, drag-n-drop, …

It should ideally be gratis software.

The features from Notepad++ I want to use in the desired Linux program (from the most important ones):

• multiple files open in tabs
• syntax highlighting for most languages
• toggle comment for most languages
• regex find and replace
• reload prompt if the file has been modified outside the program
• autosave
• find and replace in all opened files or all files in directory
• simple autocomplete (based on other text in the same file)
• hex editor

Is there any program on Linux that matches these requirements, or nearly all of them?

EDIT - Atom:
I've tried the first recommendation - Atom. Although I support the effort put into that editor, it fails to satisfy my needs for many reasons:

• Very cumbersome key bindings
• editor freezes when used after a longer time
• no show printable characters button
• UI - maybe I didn't understand it well, but why I slide right in the editor while clicking left on scrollbar?
• regex replace is terribly slow, even if the file has less then 1000 characters

I haven't tested any other feature, because the slow regex replace discourage me on its own from using the editor. Atom could be a great text editor once, but now it's not in "release state" if you ask me.

What I'm looking for:

• lightweight (non IDE) program for Linux that manages the tasks listed below
• modern GUI program - I want to use mouse, drag-n-drop, …

It should be gratis software.

The features from Notepad++ I want to use in the desired Linux program (from the most important ones):

• multiple files open in tabs
• syntax highlighting for most languages
• toggle comment for most languages
• regex find and replace
• reload prompt if the file has been modified outside the program
• autosave
• find and replace in all opened files or all files in directory
• simple autocomplete (based on other text in the same file)
• hex editor

Is there any program on Linux that matches these requirements, or nearly all of them?

EDIT - Atom:
I've tried the first recommendation - Atom. Although I support the effort put into that editor, it fails to satisfy my needs for many reasons:

• Very cumbersome key bindings
• editor freezes when used after a longer time
• no show printable characters button
• UI - maybe I didn't understand it well, but why I slide right in the editor while clicking left on scrollbar?
• regex replace is terribly slow, even if the file has less then 1000 characters

I haven't tested any other feature, because the slow regex replace discourage me on its own from using the editor. Atom could be a great text editor once, but now it's not in "release state" if you ask me.

What I'm looking for:

• lightweight (non IDE) program for linux that manage the tasks listed below.
• modern GUI program - I want to use mouse, drag-n-drop...

The features from notepad++ I want to use in the desired linux program (from the most important ones):

• multiple files open in tabs
• syntax highlighting for most languages
• toggle comment for most languages
• regex find and replace
• reload prompt if the file has been modified outside the program
• autosave
• find and replace in all opened files or all files in directory
• simple autocomplete (based on other text in the same file)
• hex editor

Is there any program on linux that match these requirements, or nearly all of them?

EDIT - Atom: I've tried the first recommendation - Atom. Although I support the effort putted into that editor, it fails to satisfy my needs for many reasons:

• Very cumbersome key bindings
• editor freezes when used after a longer time
• no show printable characters button
• UI - maybe I didn't understand it well, but why I slide right in the editor while clicking left on scrollbar?
• regex replace is terribly slow, even if the file has less then 1000 characters

I haven't tested any other feature, because the slow regex replace discourage me on it's own from using the editor. Atom could be a great text editor once, but now it's not in "release state" if you ask me.

What I'm looking for:

• lightweight (non IDE) program for Linux that manages the tasks listed below
• modern GUI program - I want to use mouse, drag-n-drop, …

It should ideally be gratis software.

The features from Notepad++ I want to use in the desired Linux program (from the most important ones):

• multiple files open in tabs
• syntax highlighting for most languages
• toggle comment for most languages
• regex find and replace
• reload prompt if the file has been modified outside the program
• autosave
• find and replace in all opened files or all files in directory
• simple autocomplete (based on other text in the same file)
• hex editor

Is there any program on Linux that matches these requirements, or nearly all of them?

EDIT - Atom: 
I've tried the first recommendation - Atom. Although I support the effort put into that editor, it fails to satisfy my needs for many reasons:

• Very cumbersome key bindings
• editor freezes when used after a longer time
• no show printable characters button
• UI - maybe I didn't understand it well, but why I slide right in the editor while clicking left on scrollbar?
• regex replace is terribly slow, even if the file has less then 1000 characters

I haven't tested any other feature, because the slow regex replace discourage me on its own from using the editor. Atom could be a great text editor once, but now it's not in "release state" if you ask me.