From what I remember (it was a while back) it was both in notepad, notepad++ and geany.
I was using, probably win xp or 7 at the time. I remember the only way I could fix it at the time was to change the language and keyboard settings to international English.
I can't seem to replicate the behavior now on win 11 even with the same language set and keyboard layout (system language set to English), so perhaps I'm misremembering?
It seems that this keyboard layout does enable typing ¨ U+00A8 so perhaps I am confused with that and that some editors (word etc) do the opening/closing replacement.
IME is not used, though interestingly in Asian languages the do used even different quotes, example Japanese:「x」and『x』
I know that some keyboard layouts come with different characters, which can be confusing when similar-looking keys are in the same place on a US-Int keyboard (nl-NL has a ¨ character almost exactly where the normal " would be for instance), but that's just the OS following the standard keyboard layout. The actual " you would want for programming is on top of the 2 in that layout. Similarly, in other keyboard layouts you will likely find the characters you intended to type with the right (shift+)altgr key combos.
The dead keys setting can be applied to any keyboard layout if you so choose (though it's usually only enabled by default for US International and regional languages that often use dead keys); you could combine dead keys with a ¨-containing keyboard layout if you so choose.
I can't seem to replicate the behavior now on win 11 even with the same language set and keyboard layout (system language set to English), so perhaps I'm misremembering? It seems that this keyboard layout does enable typing ¨ U+00A8 so perhaps I am confused with that and that some editors (word etc) do the opening/closing replacement.
IME is not used, though interestingly in Asian languages the do used even different quotes, example Japanese:「x」and『x』