Insert key

Just a passing curiosity, rediscovering an old 80s/90s trait of overtyping using the Insert key, I thought it could be a nifty time-saver given the amount of text selection and editing I do in general daily computer usage, but it doesn't work in all apps. In Plasma I can use it for instance in KWrite, and it works within LibreOffice, but it won't work when renaming a file in Dolphin. It's also redundant in Thunderbird or Firefox. Is there a setting somewhere that enables this universally or is it a complex thorny issue? gumb