In Mail, Cmd-Opt-Ctrl-F does something unexpected I would like to assign Cmd-Opt-Ctrl-F to flag an email item, but that combination in mail is already assigned somewhere, and I cannot find where that is.


It is not in System Preferences > Keyboard > Shortcuts. 
It does not seem to be on any of the Mail menus.


The action that it causes seems to be "position to a specific mail item in one of the folders". 

So I deleted that mail item. Then Cmd-Opt-Ctrl-F did not do anything, so I thought. So I went into System Preferences > Keyboard > Shortcuts and set it up.

Now when I press that combination, instead of flagging the item as desired, it positions to a different mail item in the same folder. And always that exact item.

Any ideas where Cmd-Opt-Ctrl-F is being assigned, and why it has such a weird action?
In Mavericks Mail:

The shortcut for Flag is shift- cmd - L to assign the Urgent Flag.

There is no Cmd-Opt-Ctrl-F in my Mail app.

However, if you try to add that shortcut in keyboard shortcut it will alert you if that short cut is used by someone else and show you by whom.