Add-on doesn't work anymore

[the-solipsist]

I don't know if I'm doing anything wrong, but the add-on isn't working for me anymore, not even on the test site:
https://jsfiddle.net/aaronraimist/6qrnwcjp/28/show

I click on Add Pattern, and then Save, but then the icon doesn't turn blue, and the pattern doesn't get saved.

Is there anyway one can help debug the problem to figure out where the problem is, whether some other add-on is preventing it from working, etc.?

[HenryTheVacuum]

#25

[the-solipsist]

Thanks, @HenryTheVacuum. I can't use AutoHotKey as I'm on Linux.

Also, I've since moved on to "Paste Enabler" add-on, which simply runs this javascript upon being clicked, and works on every site I've tried it on:

var allowPaste = function(e){
e.stopImmediatePropagation();
return true;
};
document.addEventListener('paste', allowPaste, true);