Some projects keep surprising me with their “solutions,” and this is one of those cases. A proposal under review by developers from GNOME and Mozilla could change how middle-mouse-button paste behaves on Linux and other Unix-like systems.
The discussions, visible in Mozilla’s Phabricator revision D277804 and a linked GNOME gsettings-desktop-schemas merge request, focus on disabling the traditional primary selection paste by default.
Mozilla proposes changing the default behavior of the Firefox browser on Unix builds so that pressing the middle mouse button no longer pastes text by default. The author of the revision frames the current behavior as a source of confusion and accidental pastes, especially when users press the middle button without expecting the clipboard contents to be inserted into text fields.
TBH, I’ve seen this cause more confusion in people than being considered helpful. Ctrl+V/Cmd+V are universally understood and behave predictably. Middle mouse click not so much. (Did you know there are two clipboards on Linux and MMB only pastes from one of them?)
I actually did not know there are two clipboards. Why/how do they work?
They’re called “selections”, the main ones being
PRIMARYandCLIPBOARD, and it’s effectively a form of IPC mediated by X. When you select something, that goes into thePRIMARYselection, while when you copy something, it goes into bothPRIMARYandCLIPBOARD.The problem is that “middle mouse click” isn’t actually paste, it’s “insert primary selection”. As long as they’re in sync you won’t notice any issue (Ctrl+V and MMB will both insert the same content), as soon as they’re out of sync you’re suddenly exposed to an implementation detail of the X11 protocol.
And it’s easy to go out of sync, simply copy something and then select unrelated text, now Ctrl+V and MMB will output different things. It can be useful, e.g. if you’re having to copy a bunch of different pieces of text from one window to another, you can simply select and MMB, no keyboard needed, but it’s not intuitive IMO, and conflicts with modern usage of the middle mouse button (Get it wrong when trying to open a link in a new tab and you’ll dump whatever text you last selected into the site instantly)
Also, these selections aren’t a thing under Wayland, it’s been re-implemented as a normal paste operation there. The question is actually whether the middle mouse button should be treated like any other mouse button or have this special behaviour by default. My vote is to expose it via the mouse settings applet and leave it up to users, like any other special mouse button.
You select the text and it magically is in this second (or actually first) clipboard. I have a habit of selecting the text I’m reading, so this selection is always something, and sometimes contains sensitive data. There were countless of situations when I was composing a long message, scrolling it and accidentally, not even noticing (it’s long already), pasted the contents. I hate this ‘feature’ and in general don’t understand who wants it and why. Disabling it would be a huge improvement for everyone, as those who need it usually know they need it, so there’s no difficulty in enabling it back.
but it’s quite intuitive to realize what it does
it isn’t if you’ve copied from an empty field by accident, or if your clipboard is empty.
interesting; how does one copy from an empty field by accidnet? /geniunely curious and oblivious
Since copy on highlight is default you literally just have to accidentally drag your mouse cursor in a terminal window and boom, you’ve copied empty text. It’s incredibly annoying.
ah i have had that happen before lol. it does copy spaces but it doesn’t overwrite your main clipboard so i don’t have qualms about it. every app you’d expect to support middle-mouse drag except notepad/gedit/kwrite/etc supports it instead of pasting unless you use chromium without the relevant extension or remain static over a textbox.
There are two clipboards in X11 - but MMB pastes from the selection not the clipboard. I have never heard of the other clipboard being used for anything and I first heard of this more than 30 years ago. (I don’t know what wayland does about clipboards, butiit acts live X11)
I’m pretty sure people who use MMB do know that it uses one of the two clipboards in Linux. Hence the reason they use it.
That being said, I find baffling that they are not setting this as an optional feature but just outright disabling it.
They are setting this as an optional feature. They are not just disabling it.
Not true, if there is no user visible setting for it. Changing a hidden gsetting via a command line is essentially removing it since it will likely bitrot and then be fully removed in a few years.
It is currently a hidden setting in Firefox’s about:config. They are removing it from there and no longer controlling it within Firefox itself so it will follow the setting set in you window manager (probably have the wrong term here, haven’t had my coffee yet), which is (generally) not hidden and available through a settings GUI. So you won’t have a web browser having different functionality than elsewhere on your machine.
If it’s hidden at that point, blame the window manager/desktop environment/whatever it’s called.
A few years ago when I tried switching, this drove me nuts. It’s so unintuitive coming from Windows where I use middle mouse all the time in browsers.
What does it do in windows, when you use it in a text field? I use this for pasting selected text from the terminal all the time, so i am quite fond of the current behaviour.
In VSCode, for instance, the middle mouse button adds extra cursors. Which is very annoying if it also pastes.
I use Ctrl+Shift+Arrow Up/Down for multiple cursors. Maybe because I’m already long time Linux user and use MMB to paste selected text.