When editing code in Eclipse, "Remote System Explorer Operation" appears in the progress bar, causing Eclipse to freeze.
Solution：
Eclipse -> Preferences -> General -> Startup and Shutdown.
- Uncheck RSE UI.
Eclipse -> Preferences -> Remote Systems.
- Uncheck Re-open Remote Systems view to previous state.
Update your Eclipse to 4.3.1 (at least) due to a bug on previous version.
Restart Eclipse and its done.