1) I suggest new feature: "RESET TO DEFAULT" and "RESET ALL TO DEFAULT" buttons in "Tools -> Preferences" dialog; the first one applies to current open section of preferences, and the latter resets all preferences to their default values.
2) I report a bug: open LyX; insert a math formula "x^2"; place the text cursor
after "2" in the superscript; press backspace; click anywhere else in the
document; LyX will crash. Deleting user settings folder (LyX recreates it when
launched) does not help.
