My sublime text user preference file get rewritten. (user/Preferences.sublime-settings)
I wrote some comments about the settings that I made (So that I can remember next time I look at the user preference file.) But it removed all the comments and reshuffle all the settings. Is it a normal behavior?
Can I keep my comments in the user preference file? I search through stackoverflow and could not find similar question.
Yes, this is normal behavior (unfortunately), and there is no way around it - it is hard-coded into Sublime. The same behavior exists in Sublime Text 3 as well. The issue has already been reported to the unofficial Sublime Text Issues repository, so the community is aware of it, but whether or not Sublime's author takes notice of it and/or fixes it is up to him alone.