> Keyboard handling is so fundamental that a text editor must deal with it, perfectly, from the beginning.
That would be nice but in reality it's such a tricky and subtle problem that nobody does it perfectly. All the operating systems and browsers are buggy in different ways, nevermind anything with smaller budgets. The deeper you get into proper text handling, the more you will realize that nobody has solved it.
Handling dead keys and displaying national characters is solved problem and has been since MS-DOS times. It's really not that "tricky and subtle problem" in 2023. Unless one is inventing keyboard handling from scratch again.
Dead keys are a drop in the ocean of what goes into international keyboard handling, and even that functions differently in every browser and OS. Which browser or OS do you think has it solved, or do you think that all of them are solved despite giving different results for the same sequence of presses?
Displaying text is an even deeper issue and also broken, the further you go from latin alphabets.
Referencing MS-DOS really takes the cake though. The Unicode standard wasn't even released until late 1991. They're still updating it even today, because it's a lot of work to handle international languages.
Perfection is unlikely, but serious developers should aim to be less buggy than the competition and/or limited by operating system and hardware shortcomings.
That would be nice but in reality it's such a tricky and subtle problem that nobody does it perfectly. All the operating systems and browsers are buggy in different ways, nevermind anything with smaller budgets. The deeper you get into proper text handling, the more you will realize that nobody has solved it.