midscroll

Windows-style middle-button drag autoscroll for Linux.

Hold the middle mouse button and drag. The page scrolls in that direction, faster the farther you drag from where you pressed, like Windows 10/11. Release to stop. A quick middle click without dragging still works as a normal middle click (paste, open link in new tab). Diagonal drags scroll both axes, so it pans wide pages too.

Prefer clicking to holding? Turn on toggle mode (in the settings GUI or TOGGLE_MODE = true) for the Windows-Explorer / Firefox style instead: one middle click starts autoscroll, the cursor moves freely, and any click stops it.

It works in every app, on Wayland and X11, because it operates at the kernel input layer (evdev in, uinput out) instead of hooking any particular desktop or toolkit.

Details:

• The speed curve is Chromium/Edge's actual Windows autoscroll formula (0.000008 * distance^2.2 px/ms, 15 px per-axis dead zone): tiny drags crawl, a full-screen drag flies.
• While scrolling, the cursor stays anchored at the press point, so the scroll stays locked to the window you started in. Dragging "over" the taskbar or another window can't steal it.
• While a drag-scroll is active, a small badge with a vertical-arrows icon appears at the anchored cursor (KDE Plasma Wayland; see notes below).
• Apps that use middle-drag themselves (FreeCAD, OrcaSlicer and Minecraft by default) are blacklisted by window class: while one of them is focused, midscroll pauses itself and the middle button behaves natively.
• The desktop and panels are left alone by default: while a desktop shell (plasmashell, xfdesktop, waybar, GNOME Shell, ...) is focused midscroll pauses, so a middle-drag can't hijack the desktop. Turn on Enable on desktop & panels (DESKTOP_SCROLL = true) if you want it there too.
• By default the cursor is anchored at the press point during a drag-scroll. Turn on free cursor (FREE_CURSOR = true) to let it follow the hand instead — useful if you dislike the locked feel, but note the scroll jumps to whatever window is under the cursor once it leaves the original one.

Install

Fedora / RPM distros

./packaging/fedora/build-rpm.sh
sudo dnf install ./dist/midscroll-*.noarch.rpm

Debian / Ubuntu

./packaging/debian/build-deb.sh
sudo apt install ./dist/midscroll_*_all.deb

Needs a release with gtk4-layer-shell packaged (Debian 13 "trixie", Ubuntu 24.04+). kdotool isn't in the Debian/Ubuntu repos, so the scroll badge needs it built from source; everything else works without it.

Arch

cd packaging/arch
makepkg -si

kdotool (for the scroll badge) is in the AUR.

Manual (any systemd distro)

sudo ./install.sh copies the files and enables the services directly; sudo ./uninstall.sh reverses it. You'll need the dependencies installed: python3-evdev, and for the badge overlay PyGObject, GTK 4, gtk4-layer-shell, librsvg and kdotool.

All methods install two services: midscroll (system, the scroll daemon) and midscroll-overlay (per-user, the badge). Package installs enable both; the overlay starts at your next login, or immediately with systemctl --user start midscroll-overlay.

Settings GUI

Search your app menu for midscroll Settings (or run midscroll-settings) for a GTK window that changes every setting - speed, dead zone, event rate, natural scrolling, the app blacklist, toggle mode and the desktop/panels toggle - with sliders and switches. Clicking Apply asks for admin authorization (via pkexec, using midscroll's own polkit action, so the prompt is scoped and briefly cached), writes /etc/midscroll.conf and restarts the daemon for you.

Tuning

Prefer a text file? Edit /etc/midscroll.conf, then sudo systemctl restart midscroll:

DEADZONE_PX = 15          # per-axis dead zone in pixels
SPEED_MULT = 0.008        # overall speed (bigger = faster everywhere)
SPEED_EXP = 2.2           # curve shape (bigger = more extreme at long drags)
PX_PER_NOTCH = 55         # px one wheel notch scrolls in your apps
TICK_HZ = 90              # scroll event rate (higher = smoother)
NATURAL = false           # true = inverted / touchscreen-style direction
TOGGLE_MODE = false       # true = click to start/stop instead of hold-drag
DESKTOP_SCROLL = false    # true = also autoscroll over the desktop and panels
FREE_CURSOR = false       # true = cursor moves freely during drag-scroll
BLACKLIST = freecad, orcaslicer, minecraft
                          # window-class substrings that pause midscroll
                          # (apps with native middle-drag); '' disables

Values are validated on load: rates and multipliers must be strictly positive, and anything out of bounds is rejected with a logged error while the default is kept.

Every tunable can also be overridden per run on the command line, which is handy for trying values without editing the config:

sudo systemctl stop midscroll
sudo midscroll --speed-mult 0.012 --tick-hz 120 --debug
midscroll --help          # full option list

--debug turns on debug logging (device probing, focus changes, scroll starts); --blacklist "app1, app2", --natural / --no-natural, --toggle-mode / --no-toggle-mode and --desktop / --no-desktop, --free-cursor / --no-free-cursor (autoscroll over the desktop and panels, and free-cursor mode) toggle the corresponding behaviors.

Pause / uninstall

Apps in BLACKLIST pause midscroll automatically while focused. For everything else:

sudo systemctl stop midscroll     # pause manually
sudo systemctl start midscroll
sudo dnf remove midscroll         # or apt remove / pacman -R

Notes

• The scroll badge is KDE-specific: it reads the cursor position through kdotool, which uses KWin's scripting API, and draws via wlr-layer-shell. On other desktops the daemon still scrolls fine; there's just no badge. (Wayland doesn't let a background process change the real pointer image, so the badge is drawn at the anchored cursor instead, which looks the same since the cursor doesn't move during a drag.)
• The app blacklist needs the focused window's class, which the root daemon can't see itself: the midscroll-overlay session service polls it (once a second, only on change is it sent) via kdotool on KDE Wayland or xprop on X11, and reports it to the daemon over the state socket. The daemon only trusts reports from a logged-in user's helper, so another local process can't feed it a fake focus and pause it. No helper running (or another Wayland desktop) just means the blacklist is inactive.
• Switching into a blacklisted app takes effect within about a second (the poll interval), and stops an in-progress scroll too. If you press the middle button in that brief window right after switching, a short scroll may start before the daemon sees the new focus and stops it.
• Pointer speed: each mouse is re-emitted through its own uinput mirror that copies the real mouse's name and vendor/product IDs, so libinput and KDE keep applying that mouse's own pointer-speed and acceleration settings. If a specific mouse still loses its speed after enabling midscroll, set it once more in System Settings -> Mouse while midscroll is running (KDE stores it per device in kcminputrc) and it will stick.
• If Firefox's built-in autoscroll is enabled (general.autoScroll in about:config), turn it off so the two don't fight. It's off by default on Linux.
• Why not a flatpak: the sandbox forbids the raw input-device and uinput access this needs, and flatpaks can't run boot-time services.
• Logs: journalctl -u midscroll -f and journalctl --user -u midscroll-overlay -f.

Security - please review the code yourself

midscroll runs a background daemon that reads every mouse (and writes a virtual one) at the kernel input layer. That is a lot of trust to hand a program you found online. Don't take my word that it's safe - read it. It's deliberately small and dependency-light so you can:

• midscroll (the daemon) and midscroll-overlay (the session badge/focus helper) are single, commented Python files - skim them start to finish.
• midscroll-apply is the only thing that runs as root on demand (via pkexec from the settings GUI); it validates every value and only ever writes /etc/midscroll.conf.
• Both systemd units are sandboxed - see systemd/*.service. Run systemd-analyze security midscroll.service and systemd-analyze security midscroll-overlay.service to see the exposure score for yourself.

Found something sketchy or a way to harden it further? Open an issue or PR - security review is genuinely welcome.

License

Public domain (the Unlicense): use, copy, modify, sell or distribute freely. The badge icon is move-vertical from Lucide (ISC license).