A lightweight, open-source, fully local alternative to Logitech Options+ for remapping every programmable button on the Logitech MX Master 3S mouse.

No telemetry. No cloud. No Logitech account required.

• macOS support — full macOS compatibility added thanks to andrew-sz, using CGEventTap for mouse hooking, Quartz CGEvent for key simulation, and NSWorkspace for app detection. See macOS Setup Guide for details.
• Remap all 6 programmable buttons — middle click, gesture button, back, forward, horizontal scroll left/right
• Per-application profiles — automatically switch button mappings when you switch apps (e.g., different bindings for Chrome vs. VS Code)
• 22 built-in actions across navigation, browser, editing, and media categories
• DPI / pointer speed control — slider from 200–8000 DPI with quick presets, synced to the device via HID++
• Scroll direction inversion — independent toggles for vertical and horizontal scroll
• Gesture button support — full HID++ 2.0 divert on Bluetooth (no Logitech software needed)
• Auto-reconnection — automatically detects when the mouse is turned off/on or disconnected/reconnected and restores full functionality without restarting the app
• Live connection status — the UI shows a real-time "Connected" / "Not Connected" badge that updates as the mouse connects or disconnects
• Modern Qt Quick UI — dark Material theme with interactive mouse diagram and per-button action picker
• System tray — runs in background, hides to tray on close, toggle remapping on/off from tray menu
• Auto-detect foreground app — polls the active window and switches profiles instantly
• Zero external services — config is a local JSON file, all processing happens on your machine

The UI shows an interactive diagram of the MX Master 3S. Click any button's hotspot dot to change its action.

Note: The architecture is designed to be extensible to other Logitech HID++ mice, but only the MX Master 3S is tested.

No install required. Just download, extract, and double-click.

1. Download → Mouser.zip (44 MB)
2. Extract the zip to any folder (Desktop, Documents, wherever you like)
3. Run Mouser.exe

That's it — the app will open and start remapping your mouse buttons immediately.

• The settings window opens showing your mouse diagram
• A system tray icon appears near the clock (bottom-right)
• Button remapping is active immediately
• Closing the window doesn't quit the app — it keeps running in the tray
• To fully quit: right-click the tray icon → Quit Mouser

• Windows SmartScreen may show a warning the first time → click More info → Run anyway
• Logitech Options+ must not be running (it conflicts with HID++ access)
• Config is saved automatically to %APPDATA%\Mouser

• Windows 10/11 or macOS 12+ (Monterey)
• Python 3.10+ (tested with 3.14)
• Logitech MX Master 3S paired via Bluetooth or USB receiver
• Logitech Options+ must NOT be running (it conflicts with HID++ access)
• macOS only: Accessibility permission required (System Settings → Privacy & Security → Accessibility)

# 1. Clone the repository
git clone https://github.com/TomBadash/MouseControl.git
cd MouseControl

# 2. Create a virtual environment
python -m venv .venv

# 3. Activate it
.venv\Scripts\activate        # Windows (PowerShell / CMD)
source .venv/bin/activate      # macOS / Linux

# 4. Install dependencies
pip install -r requirements.txt

# Option A: Run directly
python main_qml.py

# Option B: Use the batch file (shows a console window)
Mouser.bat

# Option C: Use the desktop shortcut (no console window)
# Double-click Mouser.lnk

Tip: To run without a console window, use pythonw.exe main_qml.py or the .lnk shortcut.

A Mouser.lnk shortcut is included. To create one manually:

$s = (New-Object -ComObject WScript.Shell).CreateShortcut("$([Environment]::GetFolderPath('Desktop'))\Mouser.lnk")
$s.TargetPath = "C:\path\to\mouser\.venv\Scripts\pythonw.exe"
$s.Arguments = "main_qml.py"
$s.WorkingDirectory = "C:\path\to\mouser"
$s.IconLocation = "C:\path\to\mouser\images\logo.ico, 0"
$s.Save()

To produce a standalone Mouser.exe that anyone can download and run without Python:

# 1. Install PyInstaller (inside your venv)
pip install pyinstaller

# 2. Build using the included spec file
pyinstaller Mouser.spec --noconfirm

# — or simply run the build script —
build.bat

The output is in dist\Mouser\. Zip that entire folder and distribute it.

┌─────────────┐     ┌──────────┐     ┌────────────────┐
│  Mouse HW   │────▶│ Mouse    │────▶│ Engine         │
│ (MX Master) │     │ Hook     │     │ (orchestrator) │
└─────────────┘     └──────────┘     └───────┬────────┘
                         ▲                    │
                    block/pass           ┌────▼────────┐
                                         │ Key         │
┌─────────────┐     ┌──────────┐        │ Simulator   │
│ QML UI      │◀───▶│ Backend  │        │ (SendInput) │
│ (PySide6)   │     │ (QObject)│        └─────────────┘
└─────────────┘     └──────────┘
                         ▲
                    ┌────┴────────┐
                    │ App         │
                    │ Detector    │
                    └─────────────┘

A low-level Windows mouse hook (SetWindowsHookExW with WH_MOUSE_LL) runs on a dedicated background thread with its own Win32 message pump. It intercepts:

• WM_XBUTTONDOWN/UP — side buttons (back/forward)
• WM_MBUTTONDOWN/UP — middle click
• WM_MOUSEHWHEEL — horizontal scroll
• WM_MOUSEWHEEL — vertical scroll (for inversion)

Intercepted events are either blocked (hook returns 1) and replaced with an action, or passed through to the application.

The MX Master 3S gesture button doesn't send standard mouse events. Mouser uses a 3-tier detection system:

1. HID++ 2.0 (primary, Bluetooth) — Opens the Logitech HID collection, discovers REPROG_CONTROLS_V4 (feature 0x1B04), and diverts CID 0x00C3 (gesture button). Best reliability.
2. Raw Input (fallback) — Registers for raw mouse input and detects extra button bits beyond the standard 5.
3. Middle-click fallback — When gesture button has an action but middle-click is unassigned, middle-click events route to the gesture action.

Polls the foreground window every 300ms using GetForegroundWindow → GetWindowThreadProcessId → process name. Handles UWP apps by resolving ApplicationFrameHost.exe to the actual child process.

The central orchestrator. On app change, it performs a lightweight profile switch — clears and re-wires hook callbacks without tearing down the hook thread or HID++ connection. This avoids the latency and instability of a full hook restart.

Mouser handles mouse power-off/on cycles automatically:

• HID++ layer — HidGestureListener detects device disconnection (read errors) and enters a reconnect loop, retrying every 2–5 seconds until the device is back
• Hook layer — MouseHook listens for WM_DEVICECHANGE notifications and reinstalls the low-level mouse hook when devices are added or removed
• UI layer — connection state flows from HID++ → MouseHook → Engine → Backend (cross-thread safe via Qt signals) → QML, updating the status badge in real time

All settings are stored in %APPDATA%\Mouser\config.json (Windows) or ~/Library/Application Support/Mouser/config.json (macOS). The config supports:

• Multiple named profiles with per-profile button mappings
• Per-profile app associations (list of .exe names)
• Global settings: DPI, scroll inversion, start options
• Automatic migration from older config versions

mouser/
├── main_qml.py              # Application entry point (PySide6 + QML)
├── Mouser.bat               # Quick-launch batch file
├── README.md
├── requirements.txt
├── .gitignore
│
├── core/                    # Backend logic
│   ├── engine.py            # Core engine — wires hook ↔ simulator ↔ config
│   ├── mouse_hook.py        # Low-level mouse hook + HID++ gesture listener
│   ├── hid_gesture.py       # HID++ 2.0 gesture button divert (Bluetooth)
│   ├── key_simulator.py     # SendInput-based action simulator (22 actions)
│   ├── config.py            # Config manager (JSON load/save/migrate)
│   └── app_detector.py      # Foreground app polling
│
├── ui/                      # UI layer
│   ├── backend.py           # QML ↔ Python bridge (QObject with properties/slots)
│   └── qml/
│       ├── Main.qml         # App shell (sidebar + page stack + tray toast)
│       ├── MousePage.qml    # Merged mouse diagram + profile manager
│       ├── ScrollPage.qml   # DPI slider + scroll inversion toggles
│       ├── HotspotDot.qml   # Interactive button overlay on mouse image
│       ├── ActionChip.qml   # Selectable action pill
│       └── Theme.js         # Shared colors and constants
│
└── images/
    ├── mouse.png            # MX Master 3S top-down diagram
    ├── logo.png             # Mouser logo (source)
    ├── logo.ico             # Multi-size icon for shortcuts
    ├── logo_icon.png        # Square icon with background
    ├── chrom.png            # App icon: Chrome
    ├── VSCODE.png           # App icon: VS Code
    ├── VLC.png              # App icon: VLC
    └── media.webp           # App icon: Windows Media Player

The app has two pages accessible from a slim sidebar:

• Left panel: List of profiles. The "Default (All Apps)" profile is always present. Per-app profiles show the app icon and name. Select a profile to edit its mappings.
• Right panel: Interactive mouse diagram with clickable hotspot dots on each button. Click a dot to expand an action picker with categorized chips. Changes save instantly to the selected profile.
• Add profile: ComboBox at the bottom lists known apps (Chrome, Edge, VS Code, VLC, etc.). Click "+" to create a per-app profile.

• DPI slider: 200–8000 with quick presets (400, 800, 1000, 1600, 2400, 4000, 6000, 8000). Reads the current DPI from the device on startup.
• Scroll inversion: Independent toggles for vertical and horizontal scroll direction.

• Windows & macOS only — Linux is not yet supported
• MX Master 3S only — HID++ feature indices and CIDs are hardcoded for this device (PID 0xB034)
• Bluetooth recommended — HID++ gesture button divert works best over Bluetooth; USB receiver has partial support
• Conflicts with Logitech Options+ — both apps fight over HID++ access; quit Options+ before running Mouser
• Scroll inversion is experimental — uses coalesced PostMessage injection to avoid LL hook deadlocks; may not work perfectly in all apps
• Admin not required — but some games or elevated windows may not receive injected keystrokes

Contributions are welcome! To get started:

1. Fork the repo and create a feature branch
2. Set up the dev environment (see Installation)
3. Make your changes and test with an MX Master 3S
4. Submit a pull request with a clear description

• Testing with other Logitech HID++ devices
• Scroll inversion improvements
• Linux porting
• UI/UX polish and accessibility

If Mouser saves you from installing Logitech Options+, consider supporting development:

Every bit helps keep the project going — thank you!

This project is licensed under the MIT License.

• @andrew-sz — macOS port: CGEventTap mouse hooking, Quartz key simulation, NSWorkspace app detection, and NSEvent media key support

Mouser is not affiliated with or endorsed by Logitech. "Logitech", "MX Master", and "Options+" are trademarks of Logitech International S.A.