Line Number Highlight

A Notepad++ plugin that replicates the line number behavior from VS Code: the active line number is shown in a bright color, all others are dimmed. Lightweight, zero-config, works automatically with both dark and light Notepad++ themes.

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Preview

Dark theme	Light theme
Active line: #CCCCCC · Inactive: #6E7681	Active line: #1A1A1A · Inactive: #999999

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Features

• Highlights the active line number in a distinct color
• Dims all inactive line numbers automatically
• Adapts to Notepad++ dark and light themes without any manual switching
• Separate color settings are remembered for each theme independently
• Fully customizable via a themed Settings dialog
• Works with both installed and portable Notepad++

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Installation

Standard install

1. Download LineNumberHighlight.dll from the Releases page
2. Create the folder:

   C:\Program Files\Notepad++\plugins\LineNumberHighlight\
   

3. Copy LineNumberHighlight.dll into that folder
4. Restart Notepad++

Portable install

1. Download LineNumberHighlight.dll from the Releases page
2. Create the folder:

   <Notepad++ folder>\plugins\LineNumberHighlight\
   

3. Copy LineNumberHighlight.dll into that folder
4. Restart Notepad++

The plugin will appear under Plugins → Line Number Highlight.

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Settings

Open via Plugins → Line Number Highlight → Settings

Option	Description
Active line number	Color used for the current line number
Inactive line numbers	Color used for all other line numbers
Pick color	Opens the system color picker
Reset	Restores the default color for the current theme

Settings are saved per-theme. The config file location is determined automatically:

• Standard install: %APPDATA%\Notepad++\plugins\Config\LineNumberHighlight.ini
• Portable install: <Notepad++ folder>\plugins\Config\LineNumberHighlight.ini

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Requirements

• Notepad++ v8.0 or later (tested on v8.9.2)
• Windows 10 / 11 x64 (tested on Windows 11)
• No additional runtimes or dependencies required

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Performance

The plugin uses Scintilla's SCN_UPDATEUI notification with direct function calls — no timers, no background threads, no polling. CPU impact is negligible even on large files.

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Building from source

Written in C++, requires MinGW-Builds x86_64, msvcrt variant: https://github.com/niXman/mingw-builds-binaries/releases

Download the x86_64-*-release-win32-seh-msvcrt-* build. Tested with: x86_64-15.2.0-release-win32-seh-msvcrt-rt_v12-rev0 Extract to C:\mingw32rt\ and add C:\mingw32rt\bin\ to PATH.

x86_64-w64-mingw32-g++ -std=c++14 -O2 -DUNICODE -D_UNICODE ^
  -shared -static-libgcc -static-libstdc++ -Wl,--kill-at ^
  -o LineNumberHighlight.dll src/LineNumberHighlight.cpp src/exports.def ^
  -lkernel32 -luser32 -lcomdlg32 -lgdi32 -ladvapi32

No external libraries or build systems required.

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Changelog

v1.4 — Correct 64-bit handle via NppData*, removed FindWindowW
v1.3 — Bug fixes and rendering improvements
v1.2 — Portable Notepad++ support, named constants, code cleanup
v1.1 — Unicode migration
v1.0 — Initial release

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License

Free to use, free to modify. Provided as-is with no warranty or support of any kind.

© VitalS 2026