I am using Windows 10. And yes, the new functions do not appear. Nothing happens!
Also I’m using Trial version. I installed the extension and restarted Aseprite. What happened? Nuthing. Still a keyboard shortcut.
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I see what the issue is now - the trial version doesn’t support scripts, therefore it does not support extensions. If you’re still just checking Aseprite out, and you’d like a more complete experience there are Windows binaries compiled from the open-source code, for e.g. here.
Give it a try, it should support scripts and extensions. In the future, if you’re able to I’d really recommend buying the compiled version of Aseprite, it’s convenient and supports the developer ✌️