TLDR: Stardown's default keyboard shortcuts in Firefox will need to also have Ctrl (Mac: Cmd) in them for a while.

Starting in Firefox 136 (released March 4, 2025), Firefox bug 1945032 makes some browser extension keyboard shortcuts not work well, including Alt+C which is Stardown's main keyboard shortcut. Specifically, the keyboard shortcut now does nothing unless you hold it down for about 1 second, but then the shortcut's feature starts being activated many times per second. Mozilla gave the bug a low priority so it might take them many years to fix it.

I chose Alt+C as Stardown's main keyboard shortcut because:

1. users can easily change it if they want to, and Stardown's settings page explains how
2. it makes sense and is easy to memorize because it does almost the same thing as almost the same keyboard shortcut: Ctrl+C
3. it should be as easy to press as Ctrl+C because it's the kind of keyboard shortcut that users might use as frequently as Ctrl+C
4. even though Firefox already uses Alt+C for some things (e.g. toggling "match case" when the find bar is open, and selecting "cancel" in the "add bookmark" dialog), these generally don't conflict with Stardown's use of the shortcut
5. this is Stardown's most important feature, and a tiny change to its ease of use could heavily affect how people perceive Stardown; many people are willing to learn some 2-key shortcuts but not any 3-key ones, and the same people are probably not willing to look into customizing keyboard shortcuts
6. I use it many times every day and being able to just press Alt+C was great

That is why I want Alt+C to continue being the "canonical" copy shortcut. My current plan is to change Stardown's default keyboard shortcuts only for Firefox, and only temporarily, to also have Ctrl in them (Cmd for Macs). Even though some of Stardown's shortcuts still work in Firefox 136+ without Ctrl, I will change all the defaults for consistency. Anyone that currently has Stardown installed in Firefox with a keyboard shortcut set to Alt+C might want to change the keyboard shortcut. I wish there was a keyboard shortcut available that didn't potentially conflict with access keys, but it seems all the other 2-key shortcuts are taken in Firefox--many of them by features that are rarely used.

The other ways to copy with Stardown are not affected.

Related: Firefox's keyboard shortcuts