An Alt+Tab alternative that understands tabs.
Most-recently-used switching across your windows and the tabs within them: browser tabs, terminal sessions, open documents.
For KDE Plasma on Wayland.
Alt+Tab has switched windows since Windows 3.x, around 1990. Tabs did not exist yet. Browsers would not popularise them for another decade, and it would be years after that before working in a dozen tabs at once became normal. The problem is that a browser with thirty tabs open is one window. A Konsole with six sessions is one window.
Consider working on Tab-1, then Tab-2, then wanting to go back to Tab-1. When you Alt+Tab "back to what I was last doing", you land on an entirely different application, because Alt+Tab has no concept of tabs.
Ctrl+Tab is not the answer either. It only ever moves within one application, so it cannot take you back to something in a different one. It is not universal - each application picks its own key, and plenty offer nothing. And what it does varies between applications: some cycle by recency, some step through in order, some pop up a chooser. Even where the key works, what happens next is not something you can rely on knowing.
Between them, then, you are asked to work out where you are going before you can choose how to get there: inside this application or outside it, one key or the other, and the wrong guess takes you somewhere unrelated. Consistency is king.
BackNav keeps a most-recently-used trail across windows and the tabs inside them, and gives you one shortcut to walk back along it, whichever side of an application boundary the last thing happens to be.
There are two gestures, and they don't overlap:
| gesture | what happens |
|---|---|
| Tap the shortcut | Step back one place. Repeat to keep going. You just watch windows and tabs come back into focus. |
| Hold the shortcut | A switcher panel appears. Nothing moves until you choose. |
Tap to act, hold to look.
Holding shows a list of where you have been, most recent first, with app icons and titles. Keep tapping to move down it, or let go and use the arrow keys. Enter or a mouse click confirms; Escape puts you back where you started.
If that sounds like Alt+Tab, it is meant to. The ordering is most-recently-used, not a browser's back/forward stack: going somewhere promotes it to the front rather than appending a second copy of it, and there is no branch to lose. BackNav did work like browser history early on, and it was replaced. A linear stack accumulates duplicates of the places you keep returning to, which is exactly the wrong shape for switching between a handful of things all day.
History keeps the 20 most recent places, and that is deliberate. BackNav's value is at the shallow end - the last few things you were doing.
This video shows BackNav in action.
backnav.mp4
| what BackNav restores | |
|---|---|
| Chrome, Brave, Vivaldi, Edge, Opera, Chromium | The individual tab |
| Firefox | The individual tab |
| Thunderbird | The individual mail or message tab |
| Konsole | The individual tab |
| Kate | The individual document (tab) |
| qpdfview | The individual document (tab) |
| kitty | The individual tab |
| ONLYOFFICE | The individual document (tab) |
| Any window | Raised and focused, like Alt+Tab |
Everything else still works at the window level. Nothing needs to be on this list for BackNav to be useful. The list is about how deep it can go.
Other Chromium-based browsers are one line away. The extension works in any of them, but BackNav identifies a window by the exact name KWin reports, so an unlisted browser gets window-level navigation until that name is added - see Adding a browser.
qpdfview is on that list and Okular isn't, which is worth explaining. Okular is the PDF viewer Kubuntu ships and the one most people already have; it cannot be supported, for the reason in Why some apps can't be supported. qpdfview was adopted instead, not because it is better, but because it is the tabbed PDF viewer that can be driven correctly. If you want document-level navigation in a PDF viewer, you will have to install it deliberately; it will not already be there.
Yes. Binding BackNav to Alt+Tab itself is a reasonable thing to do.
Two things to know. It learns windows as you focus them, so a window you have never once visited is not in the list. And if the daemon is not running BackNav does nothing, because the KWin script holds no logic of its own.
The shortcuts live under System Settings -> Keyboard -> Shortcuts,
where BackNav registers them under the KWin component. Search for
BackNav and you will find BackNav: Navigate Back and BackNav:
Navigate Forward.
Pick the combination you want for Navigate Back and press it into the field. Something uncontested like Meta+Tab just works. Alt+Tab is already KWin's own Walk Through Windows, so KDE will warn about the conflict and offer to reassign - accepting takes Alt+Tab away from the built-in switcher and gives it to BackNav, which is the point.
If you later want the old behaviour back, Walk Through Windows has a "reset to default" button, so nothing here is one-way.
Bind it only if it suits how you work. It does exactly one thing: undo an overshoot while a walk is still open.
A browser tab is not a window. It has no entry in the compositor, no title bar, no place in the window stack. From the outside, a browser with thirty tabs open looks exactly like a browser with one.
So there is nothing for KWin to see, and nothing for it to switch to. The only thing that knows which tab is active is the browser itself.
The extensions are a small bridge: they tell the daemon which tab is
frontmost, and switch tabs when asked. They connect to a WebSocket on
127.0.0.1 and that is the whole of it. They send tab titles and
nothing else - no URLs, no page content, no history.
They ask for no host permissions, which is the part worth caring about. Host permissions are what let an extension read page content, inject scripts or watch network requests, and an extension without them cannot do those things whatever its code says.
Tab access is not nothing, though, and it would be misleading to present it as harmless. Chrome describes it to users in terms of browsing history, because tab titles and URLs reveal where you have been. BackNav reads titles and does not send URLs - but the permission would allow it, so you are trusting the code on that point rather than the browser's sandbox. What the sandbox does guarantee is that it cannot see inside any page.
Konsole, Kate and qpdfview need no extension, because KDE applications already expose enough over D-Bus to ask them directly. kitty needs none either, though it is not a KDE application and speaks no D-Bus at all - it has its own remote-control protocol, which is richer than most of the D-Bus interfaces here.
ONLYOFFICE has neither, and is supported anyway. Which tab is active comes from the window title, which documents are open comes from the file descriptors the process is holding, and switching to one is done by handing the path back to the running instance. Nothing is asked of the application at all.
Maybe, and you can find out in about five minutes without knowing any of this codebase. The answer lives in the application, not in BackNav.
The procedure is in Probing an application, along with what to send if you want to open an issue.
Three pieces, because the information lives in three places:
backnav-kwin/, a KWin script. The only thing that can see window focus changes, and the only thing that can raise a window on Wayland.backnav-engine/, a Python daemon. Keeps the history, decides where "back" goes, talks to applications over D-Bus.browser/, WebExtensions for the browsers and Thunderbird, since tabs are invisible from outside.backnav-kwin-overlay/, the switcher panel, as a QML KWin script.
Requires KDE Plasma 6 on Wayland, and Python 3.
git clone https://github.com/davidmal1/backnav.git
cd backnav
./install.shThat installs the dependencies, both KWin scripts, and the daemon as a user service, and is safe to re-run. It stops short of three things it should not decide for you - which shortcut to bind, which browser extensions you want, and the per-application settings - and prints them at the end.
The steps it runs are written out in Installing by hand, for anyone who would rather do them themselves or wants to know what it touched.
For tab-level navigation in a browser, install the matching extension
from browser/. Without one, that browser still works at the window
level - you just get one entry for the whole browser rather than one per
tab.
The two browser builds install differently, and only one is ready to use as it sits in the repository. Thunderbird uses the same mechanism and needs a little more, so it has its own section below.
Chrome, Brave and Vivaldi load the directory directly. In a browser
tab, go to chrome://extensions, turn on Developer Mode, choose
Load unpacked and select ~/backnav/browser/chromium. Nothing to
build. The
extension id is pinned by the key field in its manifest, so it stays
the same wherever you load it from - which is what keeps BackNav's tab
bindings intact if you ever move the folder.
Firefox installs from a signed file, which is on the releases page rather than in the repository: backnav-firefox-0.2.xpi. Download it, then Add-ons and Themes -> the gear icon -> Install Add-on From File.
It is signed by Mozilla, so it installs permanently and updates itself from the releases page - there is nothing to reload by hand and no store listing involved.
Do not build this one yourself. build-xpi.sh firefox works, but release
Firefox compiles signature enforcement in and ignores the preference that
would turn it off, so what it produces is useful for validating a change
and cannot be installed. That is why this build alone is distributed as a
file: browser/README.md covers the signing route,
and why Firefox needs it when Thunderbird does not.
Each build directory has its own readme with the detail.
browser/README.md explains which build covers
which browser, and why the two Gecko builds differ so sharply given they
are nearly the same code.
kitty ships with remote control off, and without it BackNav can see the
window but not the tabs inside it. One line in ~/.config/kitty/kitty.conf,
then restart kitty:
allow_remote_control yes
Be aware of what that grants: anything able to reach kitty's socket can
run commands in your terminal and read its text, which is more than
BackNav needs. kitty offers narrower modes - socket-only and a
password-protected form - and they are worth preferring if you are
comfortable configuring them.
qpdfview needs "Restore tabs" enabled, under Preferences -> Behavior. It is off by default.
Without it qpdfview never writes the tab database BackNav reads, so the window is navigable but the individual documents are not. Nothing warns you - it simply behaves as though qpdfview had no tabs.
Not a browser, but it has tabs, and BackNav treats it exactly like one - an extension reports which tab is active. It needs two things the browsers do not.
First, the add-on. It installs from an .xpi, which is a build
artifact and deliberately not committed, so build it:
cd ~/backnav/browser
./build-xpi.sh thunderbirdThen in Thunderbird: Add-ons and Themes -> the gear icon ->
Install Add-on From File, and pick the .xpi the script printed.
Thunderbird accepts unsigned add-ons, so no store is involved, and it
survives restarts.
Second, a certificate. Thunderbird's HTTPS-Only Mode rewrites ws://
to wss:// with no fallback, so its extension connects to a second,
TLS-only port. That listener needs a self-signed certificate, and without
one the daemon simply logs a line and carries on with the other port.
Everything except the Thunderbird extension is unaffected.
Run this from the repository root, the backnav directory you cloned
into - the daemon looks for the certificate relative to its own location,
so it has to go there rather than anywhere convenient:
cd ~/backnav
mkdir -p backnav-engine/certs
openssl req -x509 -newkey rsa:2048 -nodes -days 3650 \
-keyout backnav-engine/certs/key.pem \
-out backnav-engine/certs/cert.pem \
-subj "/CN=127.0.0.1" -addext "subjectAltName=IP:127.0.0.1"
chmod 600 backnav-engine/certs/key.pemThird, restart the daemon. It reads the certificate only at startup, so one generated while it was running changes nothing until it restarts - and the next step then fails against a port that was never opened.
systemctl --user restart backnav
journalctl --user -u backnav | grep 8766 | tail -1That last line tells you whether the certificate was found - it reads
either :8766 (wss) or :8766 disabled, no certificate. If you are
running the daemon by hand instead, the same line goes to its terminal.
Fourth, trust it. Self-signed certificates are refused by default and Thunderbird will not say so - the extension simply never connects. Once per profile:
Settings -> Privacy & Security -> Certificates -> Manage Certificates -> Servers tab -> Add Exception
Location 127.0.0.1:8766 -> Get Certificate -> Confirm Security
Exception
Redo this if the certificate is ever regenerated.
browser/thunderbird/readme.md has the
background on why Thunderbird needs TLS when the browsers do not.
Optional. Copy backnavrc.example from the
repository into place and edit it:
cp ~/backnav/backnavrc.example ~/.config/backnavrcChanges take effect on the next gesture, with nothing to restart - the file is re-read when it changes rather than watched or reloaded.
Two settings, both matters of feel rather than correctness:
DwellMs- how long a pause ends a gesture. Too short and a deliberate multi-tap walk gets split into separate ones; too long and a quick bounce between two windows feels like it lags before settling.HoldMs- how long you must hold before the panel appears. Lower it if summoning it feels sluggish; raise it if an ordinary tap sometimes flashes the panel at you.
Working, and in daily use by its author, which is where most of its bug reports come from. Non-supported applications will behave like traditional Alt+Tab.
A browser takes up to a minute to come back after the daemon restarts. Extensions are not told the socket died; each reconnects on its own timer, and a minute is the worst case. Until then that browser reports nothing and shows a single window-level row.
GPL-3.0 - see LICENSE. The same licence KWin itself uses, which is the sensible default for something that runs inside it.