Comment 26 for bug 236901

I don't know how the coding in Firefox works, but I think that it might be possible to fix this by having 3 separate options for clearing private data on shutdown: 1: Don't clear that item of data; 2: Clear all of that item of data; and 3: Clear the item of private data except for what is in the current session (the one that's being closed). If this were to be done, then if one setting wants the first option and another setting wants the second option, the third option would be used. If the settings conflict can't be resolved like that, then it should at least behave consistently and notify the user.