I think whether that feels good or bad to the user depends very much on how you have layouted the page and whether different colors are used, etc. . So yes, I very much agree with you that this should be up to the website developer/JavaScript to define. Notice though that the browser makers at best have one developer working on contenteditable. So if we get a feature as you describe it, there is a chance that it will be full of bugs that won’t be fixed for another decade. That’s why I’m saying it may be better to simply get the option to enable/disable the buttons and figure our about the rest in JavaScript.
Ok, thanks for the update. The Firefox developer has been quite active in the github discussion on Input Events lately as he was implementing it. Before input events should come next, but I’ll need to write tests for them to make sure their implementations are working according to spec. I think I’ll have time to get started on that in the second half of this month.