Stop Safari from reloading tabs

Apple’s Safari web browser v5.1 has an annoying behavior where tabs reload/refresh like crazy. This can cause lost work and data.

Disable the problematic behavior this way:
1. Close Safari

2. Open a terminal and enter this command

defaults write com.apple.safari IncludeInternalDebugMenu 1

3. Restart Safari. You should see a new menu to the right of “Help” called “Debug”.

4. Select “Use Multi-process Windows” so that it no longer has a checkmark beside it.

That should fix it. (via)