Support "copy-on-select" in web UI

[JedMeister]

I use the Linux "copy-on-select; paste-on-middle-click" lots. And currently Notesium web UI does not support the "copy-on-select" bit - the "paste-on-middle-click" works fine.

TBH, I find it a constant frustration as I'm so used to using it (muscle memory?), that whenever I copy anything out of Notesium, I constantly find myself having to go back and use <CTRL><c> - then I have to use <CTRL><v> to paste (Windows style...).

I probably should just bite the bullet and use it in the terminal because then it would "just work" (default behaviour in any X app AFAIK), but I don't because I'm lazy... 😁

From what I gather after doing a bit of reading, the "copy-on-select" is more correctly called "PRIMARY selection". Hopefully these links are of some value?:

• https://specifications.freedesktop.org/clipboards-spec/clipboards-latest.txt
• https://en.wikipedia.org/wiki/X_Window_selection
• https://www.jwz.org/doc/x-cut-and-paste.html

FWIW apparently this functionality has been in X since the 90s. And whilst it seems to be an X11 specific feature, I run Wayland these days and it seems to work fine in almost all apps. I have hit a few that don't honor it, but the only one I can think of OTTOMH is Notesium! 😜

[alonswartz]

@JedMeister I can confirm copy-on-select works as expected in chrome, but does not seem to work in firefox (129.0.2).

What browser/version are you using?
Could you test to see if copy-on-select works for you here: https://codemirror.net/5/mode/markdown/

[JedMeister]

Hmm. It works on the main text, but not the code window - which I'm guessing was what you wanted me to test?

I'm not sure how much you've poked around, but here are a couple of docs that may be relevant?:

https://developer.mozilla.org/en-US/docs/Web/API/Clipboard/writeText
https://developer.mozilla.org/en-US/docs/Web/API/Clipboard/write

I'm not sure whether leveraging FF addon stuff is possible? (AFAIK they're just js snippets but I don't know... 🤣). In case it is relevant, here's another doc:

https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/Interact_with_the_clipboard

And here's a FF addon:

https://addons.mozilla.org/en-US/firefox/addon/copy-on-select-2/
https://github.com/farblos/copy-on-select-2

I haven't tested it, but am happy to if leveraging some of that might be of value?

[alonswartz]

@JedMeister sorry for the delay on this.

I don't have a fix yet, but I do have some ideas. Before attempting a fix, I need to hone in on what works, and what doesn't, and in which scenario. I've setup 2 tests:

• http://alonswartz-temp.s3-website-us-east-1.amazonaws.com/cmtest-clipboard/test1/
• http://alonswartz-temp.s3-website-us-east-1.amazonaws.com/cmtest-clipboard/test2/

Could you try test1 (specifically cm-ce (contenteditable) and let me know how it goes.
The test2 is more methodical, here are my results (where external is neovim running in a terminal).

Chrome:

Firefox:

[alonswartz]

Additionally, could you try codemirror6 and see if addresses the issue?