FIrefox addon. When I add a word to the dictionary, it does not suggest it as a correction to similar words. For example, I typed addin and added it to the personal dictionary. But when I then type adin or addon, it does not suggest addin.
This should work once you have a free account at https://languagetoolplus.com that’s used in the add-on. Without that account, the dictionary is purely local and it does indeed not work.