If you disable it, the setting should be kept in your browser's local storage. (screenshot). If you're using a private window, or if you're clearing your browser's local storage (perhaps via a privacy-extension), it will reset. Otherwise it should be permanent.
If it's not working for you, and you don't match either of those circumstances, please tell us what browser & operating system (win/mac/etc) you are using, list any privacy-related browser-extensions you use, and if possible explain how you can reliably reproduce the bug (i.e. what steps you follow after which it spontaneously resets). Thanks.