CapsLang

CapsLang is a small Windows tray app that turns CapsLock into a dedicated input-language switch key.

It does not send Win+Space, so fast typing cannot accidentally trigger shortcuts such as Win+Space+1 or Win+Space+D.

Features

• Use CapsLock to switch to the next Windows input language.
• Keep real CapsLock off during normal typing.
• Show the active Windows input language code near the text insertion caret when the active app exposes caret geometry through Windows UI Automation.
• Avoid mouse-pointer based typing feedback.
• Run quietly as a tray app.
• Manage CapsLang, indicator visibility, indicator placement, and startup from the tray right-click menu.
• Install from a release ZIP without the .NET SDK.

Download

Download the latest Windows build:

• CapsLang-Portable-win-x64.zip - standalone portable build; extract and run install-startup.ps1
• SHA256 checksums

Release builds are self-contained. No separate .NET runtime install is required.

Key Bindings

Shortcut	Action
CapsLock	Switch to the next input language and keep CapsLock off
Shift+CapsLock	Toggle real CapsLock on/off intentionally
Ctrl+CapsLock	Force CapsLock off without switching language
Tray menu Turn CapsLock Off	Force CapsLock off with the mouse

Tray Menu

Right-click the CapsLang tray icon to change runtime settings:

• CapsLang Enabled: turn the CapsLock remap on or off. When off, CapsLock behaves normally.
• Show Language Indicator: show or hide the popup indicator after language switching.
• Indicator Position:
  • Follow Text Caret: show near the text insertion caret when Windows exposes caret geometry.
  • Screen Corner: keep the indicator in the bottom-right screen corner.
• Start with Windows: create or remove the Windows Startup shortcut.
• Turn CapsLock Off: force real CapsLock off.

Settings are saved under %LOCALAPPDATA%\CapsLang\settings.json.

The indicator is not limited to Thai and English. It uses the active Windows input language culture, such as EN-US, TH-TH, JA-JP, KO-KR, or ZH-CN.

Install From Release ZIP

1. Open the repository's Releases tab.
2. Download CapsLang-Portable-win-x64.zip.
3. Extract the ZIP.
4. Run PowerShell in the extracted folder.
5. Run:

.\install-startup.ps1

The installer creates a Windows Startup shortcut and starts CapsLang.exe. You can later turn Startup on or off from the tray right-click menu.

Disable any PowerToys CapsLock remap while CapsLang is running, otherwise both tools may react to the same key.

Uninstall

Run this from the same extracted release folder:

.\uninstall-startup.ps1

Build From Source

Requirements:

• Windows
• .NET 8 SDK

Run:

dotnet build

To install from source:

.\install-startup.ps1

When CapsLang.exe is not present in the current folder, the installer builds a framework-dependent local publish output with the .NET SDK and points the Startup shortcut at that build.

Publish Release Assets Locally

.\scripts\publish-release.ps1

The release assets are written to artifacts/release.

GitHub Release Workflow

Push a version tag to publish a release:

git tag v0.1.0
git push origin v0.1.0

The GitHub Actions workflow builds a self-contained win-x64 release ZIP and checksum file, then uploads them to the GitHub Releases tab.

Release assets:

• CapsLang-Portable-win-x64.zip
• CapsLang-SHA256SUMS.txt

Notes

• If CapsLang should work inside elevated administrator apps, run CapsLang as administrator too. Normal non-admin apps work without elevation.
• Caret detection uses Windows UI Automation TextPattern2 first, then older text/Win32 caret APIs. Some apps still do not expose exact caret geometry; in those cases CapsLang anchors the popup to the focused window instead of the mouse pointer.
• CapsLang is Windows-only.

License

MIT