# Little Big Mouse: fixing multi-DPI mouse crossover on Windows and Linux > Little Big Mouse corrects the pointer's crossing point between monitors with different pixel densities, and version 5.6.0 adds live preview, per-edge resistance and a rescue shortcut. It is a Windows-first tool with an experimental Linux port. **mgth/LittleBigMouse** — DPI Aware mouse move across screens - Repository: https://github.com/mgth/LittleBigMouse - Stars: 6,649 · Forks: 285 - Language: C# - License: GPL-3.0 - Published: 2026-09-22 · Updated: 2026-09-22 · Language: en - Canonical page: https://hysenlabs.com/projects/mgth-littlebigmouse ## The crossover point problem Little Big Mouse targets Windows positions monitors by their pixel rectangles, but it does not reconcile those rectangles with the physical size of the panels. Put a 4K screen next to a full HD screen and the two are treated as if a pixel were the same physical distance on both. The pointer then crosses the edge at the wrong height or width. The cursor jumps, or it arrives on the second monitor far from where the eye expects it. Little Big Mouse is aimed at exactly that setup, and the README names the 4K plus full HD pairing as the typical case. It is a Windows 10 and 11 tool first. The audience is anyone who has scaled displays at different factors and has learned to live with an approximate border. It is not a general display manager, and it does not replace the vendor control panel or the Windows display settings; it adjusts how the pointer behaves at the seams between screens. ## How the pointer is intercepted and rewritten The mechanism is a hook that sits between the physical mouse and the system pointer. On Windows, the release notes for 5.6.0 state that the C++ hook has been removed and the Rust daemon is now the only one. On Linux, the README describes an evdev/uinput backend that grabs the physical mice and drives a virtual pointer, with Wayland-portal and X11 fallbacks. The same idea applies on both: read the raw movement, apply the layout and resistance rules, and emit corrected movement to a virtual device. The layout itself is a set of monitor rectangles. The 5.6.0 notes say automatic placement had lost the vertical offset between neighbouring screens, so a monitor sitting slightly higher came out a full screen height away, and that the first layout shown did not match what Place from windows config produced afterwards. Both directions now round-trip. Border resistance is defined as sections along any edge, each with its own value, and separate settings for moving the pointer and for dragging a window. Live update pushes edits to the mouse engine as you make them, without saving, so a resistance or position can be felt before it is kept. ## Installing on Windows and a first layout The README gives a five-step Windows path: download the latest release from the Releases page, run the installer, optionally change the install path, follow the progress, then open the program from the Start Menu. The 5.6.0 release notes add a runtime requirement: the .NET 10 Runtime (x64). After the first launch, the workflow is to let the tool place the monitors, compare that against Place from windows config, and then adjust. The 5.6.0 notes describe the automatic placement as now matching the Windows configuration, so that comparison is the first thing worth checking. Live update is selected from the arrow next to the apply button, which is where a layout can be tried without committing it. If a layout traps the cursor, the documented recovery is a keyboard shortcut: ```text Ctrl+Alt+Shift+M ``` Holding that combination returns the mouse, and the notes say it is configurable in the options. The rescue shortcut is Windows-only for now; the Linux release follows separately. On Arch Linux the README gives the AUR route, which builds the Rust hook daemon and the Avalonia UI from the tagged sources: ```bash paru -S littlebigmouse # or: yay -S littlebigmouse ``` The package places the app in /usr/lib/littlebigmouse with littlebigmouse on the PATH, adds a desktop entry and icon, and installs a udev rule granting the input group write access to /dev/uinput. It depends on dotnet-runtime-10.0 rather than bundling .NET, while ddcutil, kscreen and argyllcms are optional dependencies for brightness and contrast control, Plasma layout detection and colorimeter support. One manual step remains, because a package cannot add a user to a group. The README shows the command as sudo gpasswd, truncated at that point, and points to the Linux section for joining the input group. Treat the exact group-adding syntax as something to confirm in the repository rather than copy from a secondary source. ## Where Little Big Mouse gets in the way The Linux port is explicitly labelled experimental. It is developed and tested on KDE Plasma 6 with Wayland, and the README asks for feedback from other desktops on the issues page. That is a real boundary: on GNOME, on other Wayland compositors, or on an X11 session, the evdev/uinput path and its fallbacks may behave differently from the tested configuration. The rescue shortcut, which is the one recovery that does not need a click, is Windows-only for now, so a Linux user whose layout traps the cursor has less to fall back on. There is also a supply-chain hazard the project calls out itself. The README warns that littlebigmouse.com is not affiliated with the project and is used to distribute malware. The only official sources named are the GitHub repository with its Releases page and littlebigmouse.mgth.fr. Anyone searching for a download and landing on the other domain is outside the project's control. Finally, the tool is not a colour calibration suite or a monitor control panel. Brightness, contrast and colour profiles are offered, but on Linux they depend on optional packages such as ddcutil and argyllcms, so those features are only as present as the dependencies you installed. ## What a display control panel does differently The nearest alternative for many users is the display configuration built into the operating system or the GPU vendor's control panel. Those tools change resolution, scaling factor and monitor arrangement, and they are the right place to start. The difference is where the correction happens. Changing the scaling factor alters what every application renders and how much desktop space each monitor contributes. Little Big Mouse leaves the rendering alone and rewrites pointer movement at the seam, so a 4K panel keeps its native scaling while the crossing point is corrected. That is a narrower intervention, and it is also a more fragile one, because it depends on a hook staying attached to the input path. On Linux, a compositor-level or kernel-level answer is a different trade: it sits in the display stack rather than beside it, but it is tied to the compositor's own model of the layout. The README does not document a comparison with those approaches, so the choice comes down to whether you want the correction inside the display settings or between the mouse and the pointer. ## Maintenance, releases and the GPL-3.0 licence The repository is not archived, and the last push was on 2026-09-17. Releases are frequent: v5.5.0 on 2026-07-25, v5.5.1 on 2026-07-26, and v5.6.0 on 2026-07-31, with the 5.6.0 notes listing fixes and features numbered #522, #524, #525, #528, #530 and #531, and mentioning that the test suites now run in CI. That is a steady cadence, and it also means upgrade cost is real: the 5.6.0 release requires the .NET 10 Runtime (x64), and the AUR package depends on dotnet-runtime-10.0 rather than bundling it, so runtime updates arrive through the distribution's package manager. A jump between minor versions can change layout behaviour, as the 5.6.0 notes show for automatic placement. The project is licensed GPL-3.0. That is a copyleft licence, and it matters if you plan to redistribute a modified build or link it into a product; the repository also carries a PRIVACY.md and a SIGNING.md, which are worth reading before shipping anything. This is a description of the licence terms, not legal advice. Consult your own counsel for a specific case. ## Conclusion Adopt Little Big Mouse if you run Windows 10 or 11 with monitors at different DPI scaling and the pointer lands in the wrong place when it crosses an edge. Skip it if you need a supported macOS build, or if a KDE Plasma 6 Wayland desktop is not your target, since the Linux port is described as experimental and tested there. Before trusting a layout, verify that the automatic placement matches the Windows configuration, that the Ctrl+Alt+Shift+M rescue shortcut recovers the cursor, and that you installed the .NET 10 Runtime x64, which the 5.6.0 release requires. ## FAQ ### What does Little Big Mouse do? It corrects where the mouse pointer crosses between monitors when those monitors use different DPI settings, a case the README illustrates with a 4K screen beside a full HD screen. It also adds screen looping, border resistance, display size adjustments and colour and brightness balancing. ### How do I install Little Big Mouse? On Windows, download the latest release from the Releases page, run the installer, and open the program from the Start Menu; version 5.6.0 requires the .NET 10 Runtime (x64). On Arch Linux, the README gives paru -S littlebigmouse or yay -S littlebigmouse from the AUR. ### How do I set up Little Big Mouse for dual monitors? After installing, check that the automatic placement matches Place from windows config, then adjust positions, sizes and per-edge resistance. Live update, chosen from the arrow next to the apply button, sends changes to the mouse engine without saving them. ### Is Little Big Mouse safe to download? The README warns that littlebigmouse.com is not affiliated with the project and is used to distribute malware, and names only the GitHub repository with its Releases page and littlebigmouse.mgth.fr as official sources. Download from those and not from the other domain. ### Does Little Big Mouse work on Linux? There is a Linux port, described in the README as experimental and developed and tested on KDE Plasma 6 with Wayland, using an evdev/uinput backend with Wayland-portal and X11 fallbacks. Arch Linux users can install it from the AUR, and one manual step remains: joining the input group. ### How do I use Little Big Mouse? Install it, let it place your monitors, compare that with Place from windows config, then adjust positions, sizes and border resistance, using live update to feel changes before keeping them. If a layout traps the cursor, hold Ctrl+Alt+Shift+M on Windows to get the mouse back. ## Sources - [Issues](https://github.com/mgth/LittleBigMouse/issues) - [License: GPL-3.0](https://github.com/mgth/LittleBigMouse/blob/master/LICENSE) - [mgth/LittleBigMouse on GitHub](https://github.com/mgth/LittleBigMouse) - [README](https://github.com/mgth/LittleBigMouse/blob/master/README.md) - [Releases](https://github.com/mgth/LittleBigMouse/releases) --- Hysen Labs editorial analysis, written from the project's own repository and release notes. Cite the canonical page: https://hysenlabs.com/projects/mgth-littlebigmouse