"Show Character Alternates" checkbox under the Type preference pane is not clickable. While trying to disable the annoying Glyph popup window I discovered that I cannot change this preference setting. I was able to change the setting by manually directly editing Illustrators preference file manually which reflects the change when relaunching the program, however it can not be changed through the UI.

MacOS Sierra 10.12.8
Illustrator 23.0.4