Mac OS X: Bypass the confirmation message when turning on private browsing in Safari

When turning on "Private Browsing" in Safari, it always pops up a confirmation window:

It is annoying. To avoid the confirmation message, you have two options:

• Option 1: Hold Option key, when click "Private Browsing..." menu item
• Option 2: Add keyboard shortcut:
  1. "System Preferences..." -> "Keyboard"
  2. Activate "Keyboard Shortcuts" tab, select "Application Shortcuts", then click + button
     
     
  3. Application: Safari.app, Menu Title: Private Browsing, Keyboard Shortcut: Ctrl+Option+P, then click Add button. You can now using the key combo (shortcut) to turn on "Private browsing" mode without seeing the confirmation message.