Files
middleclick-autoscroll/README.md
T
Felitendo f42d80598f fix: keep Steam out of an endless update loop
Steam compares its installed files against its manifest at every start and
restores whatever differs, which is why its launcher entry carries
-noverifyfiles. The entry in ~/.config/autostart never got it: it points at
/usr/bin/steam, a shell script, so it fell through the Chromium filter in
mca_autostart_apply and was left alone.

A Steam started at login therefore verified, found the web helper script 46
bytes larger than the manifest says, restored it, and the path unit patched
it straight back - an update dialog that begins again every few seconds and
never finishes. The same client started from the menu was fine, which is
what made it look like a problem of Steam's own.

The autostart entry now carries the switch as well. It follows the Steam
setting rather than the autostart one, because leaving it out while Steam is
patched is exactly what causes the loop.

That covers the entry that exists; a terminal or a script still starts Steam
without the switch. So the patch no longer fights back either: a script that
was patched before, is not patched now, and belongs to a client that is
still running has just been restored by Steam, and doing it again would only
have the two of them undoing each other. It waits for the next apply with
Steam closed - the helper is started once, at the start, so patching it now
would not have helped that session anyway.

Also: Steam does not checksum that script, it compares sizes - the log says
"Verifying file sizes only" - while the comments and the documentation
claimed otherwise. And the status screen now tells a patch that is waiting
from one that is missing, instead of reporting both as not patched yet.
2026-08-24 10:01:27 +02:00

206 lines
7.8 KiB
Markdown

# middleclick-autoscroll
Middle-click autoscroll — hold the middle mouse button, move the pointer, the
page scrolls — in every application on the system that can do it, and in
anything installed later.
There is no list of supported applications to check against and none to keep up
to date. Every launcher on the system is examined, the ones running on Chromium
underneath are identified by what they ship rather than by their name, and each
of them is handled.
```bash
paru -S middleclick-autoscroll
middleclick-autoscroll enable
```
That is the whole setup. Nothing else has to be configured, and no file has to
be edited.
## Why this needs a program at all
Blink — the engine inside Chromium, Electron and CEF — has had Windows-style
autoscroll for years. On Linux it is switched off, because middle click is
already taken by primary-selection paste. One command line argument turns it
back on:
```
--enable-blink-features=MiddleClickAutoscroll
```
Getting that argument into one application is a five-minute job. Getting it into
all of them, in a way that survives the next package upgrade, is not:
- Some applications read a flag file, some don't.
- Some ship their own copy of Electron, some use the system one.
- Flatpaks see none of the host's configuration.
- An application that starts itself at login uses a different entry than the one
in the menu, and Discord launched at login used to behave differently from
Discord launched by hand.
- Steam takes no arguments for its interface at all, and puts back any file you
change.
- Every upgrade can undo the lot.
## The interface
`middleclick-autoscroll` on its own:
```
Middle-Click Autoscroll
Autoscroll ON
Applications covered 14 of 15
Not identified 1 - see the applications list
Steam ON
New applications ON
Last applied 3 minutes ago
Applications pick this up the next time they are started.
[1] Turn autoscroll on or off
[2] Re-apply everything
[3] Applications
[4] Settings
[q] Quit
```
**[3] Applications** lists everything that was found, how each one is handled,
and lets a single application be switched off — or an unrecognised one switched
on — with the space bar:
```
Applications
▸ Vesktop on (flag file)
Discord on (flag file)
Code - OSS on (flag file)
Obsidian on (flag file)
Signal on (flag file)
Spotify on (launcher)
Steam on (Steam)
Cursor cannot tell
```
**[4] Settings** has the categories — Electron and CEF applications, browsers,
Flatpaks, autostart entries, Steam, Spotify, whether to watch for new
applications, and a field for extra Chromium arguments if you want any.
There is a configuration file behind all of this. You are never asked to open
it.
## Where the argument actually goes
Two routes, picked per application.
| | |
|---|---|
| **Flag file** | Arch's Electron and Chromium wrappers read extra arguments from `~/.config/<name>-flags.conf`. This is the good one: it is the supported way to pass arguments, it survives package upgrades untouched, and it applies to a launch from a terminal as much as one from the menu. |
| **Desktop entry** | For applications that ship their own binary with no wrapper, and for Flatpaks, a copy of the entry with the argument appended goes into `~/.local/share/applications`, where it shadows the system one. |
Entries that already live in `~/.local/share/applications` — AppImages, web app
shortcuts — are edited in place and the original is kept. So are the entries in
`~/.config/autostart`, so an application that starts itself at login gets the
same treatment as one started from the menu.
An `--enable-blink-features` that is already there is **extended**, never
repeated. Chromium keeps only the last occurrence of that option, so a second
one would silently switch off whatever the first one enabled.
## Steam
Steam's interface is CEF and supports the feature perfectly well, but Steam
builds the command line for its web helper itself and offers no way to add to
it. The only place an argument fits is the script that starts the helper, inside
Steam's own installation:
```
~/.local/share/Steam/ubuntu12_64/steamwebhelper_sniper_wrap.sh
```
Steam compares the installed files against its manifest at every start — by
size, not by content — and restores whatever differs, so its launcher entry gets
`-noverifyfiles`. So does its entry in `~/.config/autostart`, which Steam writes
as soon as it is set to run at login: that one bypasses the menu entry entirely,
and without the switch a Steam started at login finds the patched script,
restores it, gets patched again, and never gets past its update dialog.
**The trade-off is real**: with verification off, Steam no longer repairs a
damaged installation by itself. That is why Steam is a switch of its own rather
than part of the general handling — turn it off in the settings and Steam is
left completely alone.
The script comes back on every client update. The watcher notices and puts the
patch back.
Starting Steam some other way — from a terminal, from a script — leaves the
switch out and Steam puts its own copy back for that session. The patch returns
at the next apply with Steam closed; it is deliberately not repeated while the
client is running, because the two would only undo each other and the helper is
started once, at the start.
## Applications installed later
A systemd user path unit watches every directory a launcher can appear in —
`/usr/share/applications`, the Flatpak exports, `~/.local/share/applications`,
`~/.config/autostart` — plus Steam's helper script. Anything new is handled
within a second of being installed, whether it came from pacman, the AUR,
Flatpak or an AppImage manager. There is no hook to install per package manager.
## What it will not guess
An AppImage keeps its payload in a compressed filesystem, so there is no way to
tell from the outside whether Chromium is in there. Those show up as **cannot
tell** and are left alone until you switch them on from the applications screen.
Detection is deliberately conservative everywhere else too. A wrong "yes" would
append an unknown argument to something that is not Chromium, and plenty of
programs treat an unrecognised argument as a file name to open.
## Undoing it
```bash
middleclick-autoscroll disable
```
Every change is recorded in a ledger as it is made, and `disable` replays it
backwards: generated entries are deleted, edited files are restored from their
backups, flag files that only ever contained our line are removed, and a flag
file that was merged into loses exactly the one feature that was added to it.
Files that were not touched by this program are not touched by it now either.
Run this before uninstalling the package.
## Commands
| | |
|---|---|
| `middleclick-autoscroll` | the menu above |
| `… enable` | turn it on, apply, start watching |
| `… disable` | turn it off and put everything back |
| `… apply` | apply to anything new (this is what the watcher calls) |
| `… apply --rebuild` | take everything back and apply it again, to repair a mess |
| `… status` | what is covered |
| `… list` | every application that was found and how it is handled |
See `man middleclick-autoscroll` for the details.
## Requirements
Arch or an Arch derivative (CachyOS, EndeavourOS, Manjaro), bash, systemd for
the watcher. Nothing outside your home directory is ever written to, and running
it as root is refused.
## Building from source
```bash
make
sudo make install
```
`make check` runs `bash -n` and, if installed, `shellcheck` over every script.
## License
GPL-3.0-or-later.