Different file has different spaces for per tab

[canvasT]

my sublime text 2’s version is Version 2.0.1 build22.17
os is osx 1.8.3

I set per tab has four spaces, it works fine in most files,but some file has two spaces for per tab.

[FichteFoll]

Preferences.sublime-settings

// Set to false to disable detection of tabs vs. spaces on load "detect_indentation": true,