Serious problem with a file

[jrbminn]

(I posted this yesterday to the discussion forum by mistake, now I’ve moved it here and updated it.)

I’m a very new user, getting started with sublime 2. Running ubuntu linux. My main activity right now is editing a medium sized latex file, 60+ pages.
Using LaTeXTools, Package Control, and the BracketHighlighter package. (I put the last package in recently to facilitate matching braces inside math environments.)
Seemed to work, but:
yesterday when opening the file for futher work, I find 4000+ lines of little phrases from the text, and the rest of the file is gone.
The content of the lines seems to be based their role in latex (blank lines first, then commands in alphabetical order, then non-commands in alphabetical order).

It is always possible that I hit an incorrrect key by mistake. But it’s hard to imagine why that would lead to this result.

Does anyone have an idea what might have happened? I have backup files, so I’ve only lost a day’s work. Since my main editing task involves latex, if I can’t discover what happened I obviously will not be able to use this editor in the future.
Thanks,
John

[tito]

F9 is the key, to sort lines… I use it frequently to deduplicate things

[jrbminn]

Thank you, I’ve tested F9 on another copy of my file and it does produce a similar result. I notice that F9 acts whether or not anything is selected. I couldn’t see a way to modify this behavior so I’ve disabled the key for now.
I appreciate your help!