Clean-up FlagSetting and remove misuse.

In a few places, FlagSetting is used as a general mechanism for local save/modify and restore. This is not the intention. Instead, use a general mechanism in these cases and preserve FlagSetting for its intended purpose. Now, FlagSetting (and friends) can be based on the same general pattern for local save/modify and restore.

This will separate the current use-cases (of FlagSetting) in order to remove/replace the brittle use of FlagSetting and friends (after related re-work).